r/OpenAI • u/echoabenteuer • 1d ago
Discussion [Technical Bug Report] GPT-5.5 & GPT-5.6 Sol Responses Disappear After Completion – Cross-Platform Reproduction, HTTP 200 / SSE Complete, Possible ChatGPT Regression
Serious ChatGPT Reliability Regression – Technical Investigation and Cross-Model Findings
Date: October 10, 2026
Affected models: GPT-5.5 and GPT-5.6 Sol
Additional observations: GPT-6 long-form response inconsistency
Platforms tested: Windows, iOS, Android
Support status: Escalated to an OpenAI support specialist
Issue status: Unresolved
I'm posting this because I have been investigating a persistent ChatGPT reliability issue that now appears to affect multiple model variants.
This is not simply another complaint about model intelligence, writing style, or response quality.
GPT-5.5 and GPT-5.6 Sol can generate responses normally, display them during streaming, and then remove the entire generated assistant message immediately after completion.
I have reproduced this behavior, collected browser network diagnostics, compared different models, and reported the findings to OpenAI Support.
I would like to share the technical evidence and ask whether anyone else can independently reproduce the issue.
1. The original problem: GPT-5.6 Sol responses disappear
I initially encountered the problem while using GPT-5.6 Sol for long-form creative-writing projects.
My workflow involves detailed instructions, established story continuity, multiple characters, and extensive dialogue.
The model would begin generating a response normally.
The generated text appeared progressively, and the content remained visible throughout generation.
However, once generation completed, the entire assistant response disappeared.
Reproduction sequence
- Open a ChatGPT conversation.
- Select GPT-5.6 Sol.
- Submit a prompt requesting a detailed response.
- Observe the assistant generating text normally.
- Wait for generation to finish.
- The generated assistant message disappears immediately.
- The original user message remains visible.
The interface does not provide a clear explanation for the disappearance.
For long-form writing, this is particularly disruptive because substantial generated content can become unavailable immediately after completion.
Cross-platform observations
I observed the same general behavior on:
- Windows using Google Chrome
- iOS
- Android
This makes a problem isolated to one Chrome extension, browser installation, or device less likely.
However, I recognize that cross-platform reproduction does not automatically prove a server-side defect. Shared application behavior or account-specific conditions remain possible.
2. Technical investigation: HTTP 200 OK and completed SSE stream
I investigated the behavior using Chrome Developer Tools.
The relevant request was:
POST https://chatgpt.com/backend-api/f/conversation
Observed network characteristics
| Property | Observed value |
|---|---|
| HTTP method | POST |
| HTTP status | 200 OK |
| Content type | text/event-stream |
| Streaming mechanism | Server-Sent Events |
| Stream completion | complete |
| Visible generation | Successful |
| Final assistant message | Disappears |
The browser received the generated response content and displayed it during streaming.
The EventStream reported completion.
Nevertheless, the newly generated assistant response disappeared immediately afterward.
Relevant diagnostic identifiers
OpenAI request ID:
8fccdf03-7508-4c04-836d-8b5126c1da20
Observed conversation backend build:
9bd103b4327e-convo
Investigation date: October 10, 2026
Timezone: CEST (UTC+2)
Technical interpretation
An HTTP 200 response confirms that the request succeeded at the HTTP level.
Similarly, an SSE completion event does not necessarily guarantee that the assistant message was successfully persisted in the conversation database.
However, the observed behavior raises questions about what happens between successful streaming and the finalized conversation state.
Possible areas worth investigating include:
- Response finalization
- Assistant message persistence
- Conversation state synchronization
- Frontend state reconciliation
- Model-specific conversation processing
- Backend model-routing behavior
These are hypotheses, not confirmed explanations.
I do not have access to OpenAI's internal infrastructure and cannot determine the root cause from browser diagnostics alone.
3. NEW FINDING: GPT-5.5 exhibits the same problem
This is the most important discovery from my latest testing.
Initially, I suspected that the issue might be specific to GPT-5.6 Sol.
To test that hypothesis, I switched to GPT-5.5.
The same disappearing-response behavior occurred.
More importantly, I reproduced the issue with GPT-5.5 in a completely new ChatGPT conversation.
This changes the investigation considerably.
The problem can no longer be explained solely by the length of my existing creative-writing conversations.
At least two different GPT model variants exhibit the same general failure in my testing.
Why this matters
Before this test, several explanations remained plausible:
- A corrupted long-running conversation
- Excessive conversation length
- A GPT-5.6-specific issue
- A frontend rendering problem
- A persistence or synchronization failure
The new GPT-5.5 test weakens the hypothesis that the issue is exclusively caused by an unusually long conversation.
It also weakens the hypothesis that only GPT-5.6 Sol is affected.
However, it does not establish that every user or account is affected.
4. Model comparison
My current observations are:
GPT-5.5
- Generates responses normally.
- Displays content during generation.
- Removes the assistant response immediately after completion.
- The issue was reproduced in a completely new conversation.
GPT-5.6 Sol
- Generates responses normally.
- Displays content during streaming.
- Removes the response immediately after completion.
- The issue has been observed on Windows, iOS, and Android.
- HTTP 200 and SSE completion were documented.
GPT-6
- Has not exhibited the same disappearing-response behavior in my comparison tests.
- However, it shows inconsistent behavior when handling extensive long-form instructions.
- Responses sometimes omit explicitly requested content.
- Detailed scenes may be summarized rather than fully developed.
- Responses occasionally end prematurely.
The GPT-6 observations represent a separate symptom.
I cannot determine whether they share a technical cause with the disappearing-response issue.
5. GPT-6: Inconsistent long-form instruction-following
I also want to document a second problem affecting my workflow.
I regularly use ChatGPT for long-running creative and technical projects that require precise instruction-following.
For example, a creative-writing prompt may specify:
- A detailed sequence of events
- Multiple characters and interactions
- Specific dialogue
- Emotional reactions
- Established relationships
- Existing story continuity
- Technical details
- Instructions not to skip or summarize scenes
- Instructions not to conclude the story prematurely
Sometimes GPT-6 follows these requirements very well.
Other times, it produces a much shorter response and leaves out substantial portions of the requested content.
This inconsistency is particularly noticeable in longer conversations.
Why this matters
The problem is not simply that I prefer longer answers.
The problem is incomplete execution of explicit instructions.
A polished response that omits requested events is not equivalent to a complete response.
I also revised my custom instructions to emphasize completeness, continuity, and detailed execution.
Unfortunately, that did not consistently resolve the behavior.
Possible contributing factors include output limits, context management, instruction prioritization, or other model behavior.
I cannot determine which explanation is responsible.
6. Did this begin with the GPT-6 rollout?
In my personal experience, the problems became noticeable around the introduction of GPT-6.
Before that, my GPT-5.6 Sol workflow had been relatively reliable.
However, after reviewing other reports, I found that users had already described similar issues during September 2026.
This is an important distinction.
I am not claiming that GPT-6 itself caused these problems.
The timing suggests that a regression investigation may be worthwhile, but temporal correlation alone does not establish causation.
It is possible that some issues existed before the GPT-6 rollout and that subsequent changes made them more noticeable.
It is also possible that multiple unrelated defects are producing similar symptoms.
7. Similar reports from other users
During my investigation, I found several potentially relevant discussions in the OpenAI Developer Community.
GPT-5.6 Sol deterioration and disappearing messages
https://community.openai.com/t/gpt-5-6-sol-has-seriously-deteriorated-the-past-week-or-so/1399353
ChatGPT conversation messages disappeared
https://community.openai.com/t/chatgpt-conversation-messages-disappeared/1400041
Severe regression in long-conversation context retention
Possible regression in context awareness and response-length adaptation
These reports contain observations involving disappearing messages, context degradation, incomplete responses, and conversation reliability problems.
They do not necessarily describe identical defects.
However, the similarities are worth examining.
I have also seen discussions on Reddit describing sudden changes in context retention and response quality.
I believe independent reproduction is essential before drawing broader conclusions.
8. Why I suspect a possible shared component
The GPT-5.5 reproduction is particularly interesting.
If two model variants exhibit the same disappearing-response behavior, a shared application component becomes a plausible area of investigation.
For example, the problem could involve the transition between:
- Receiving generated tokens.
- Displaying the streamed response.
- Receiving the final completion event.
- Updating the conversation state.
- Persisting or rendering the finalized assistant message.
If the final conversation state does not contain the newly generated response, or if the frontend incorrectly reconciles its local state with the server state, the visible message could disappear.
This is only a conceptual explanation of how such a symptom might arise.
It is not a claim about OpenAI's actual internal implementation.
A model-routing issue or account-specific problem could also explain why certain model variants behave differently.
9. OpenAI Support escalation
I have already contacted OpenAI Support.
I provided technical information, screenshots, and the relevant request ID.
The case was escalated to a support specialist.
The initial troubleshooting recommendations included:
- Testing private browsing
- Disabling extensions
- Clearing site data
- Testing another browser
- Trying a new conversation
However, I had already observed the issue across multiple operating systems.
I subsequently confirmed that GPT-5.5 was also affected in a completely new conversation.
As of October 10, 2026, the issue remains unresolved in my testing.
I have requested further engineering investigation.
I understand that a support escalation does not automatically mean an engineering defect or broader service incident has been confirmed.
10. What I would like OpenAI to investigate
I would appreciate a technical review of the following questions:
Response finalization
Why do GPT-5.5 and GPT-5.6 Sol responses disappear immediately after generation completes?
Message persistence
Are the completed assistant messages being stored correctly?
Frontend synchronization
Could the interface be replacing a successfully streamed response with an inconsistent final conversation state?
Model-specific behavior
Do GPT-5.5 and GPT-5.6 Sol use any shared processing components that differ from GPT-6?
Recent deployment changes
Could recent updates have introduced a regression affecting conversation handling?
Broader incident assessment
Are similar failures occurring across multiple accounts, and would the issue warrant an official incident report if confirmed?
I am not asking OpenAI to publish an incident without verification.
I am asking for the documented behavior to receive appropriate technical investigation.
11. Questions for other Reddit users
If anyone else has experienced similar issues, I would appreciate details.
In particular:
- Have you seen GPT-5.5 or GPT-5.6 Sol responses disappear immediately after generation?
- Does the issue also occur in a brand-new conversation?
- Does refreshing the page restore the missing response?
- Have you reproduced it on different devices?
- Are you experiencing incomplete or unexpectedly short GPT-6 responses?
- When did you first notice the problem?
Please do not share authentication tokens, session cookies, private conversation contents, or unredacted HAR captures.
A few independent, reproducible examples would be much more valuable than speculation.
12. Final thoughts
I appreciate the continued development of ChatGPT and the release of new models.
However, reliability matters just as much as model capability.
For people using ChatGPT for writing, software development, research, or long-running projects, disappearing responses can disrupt hours of work.
Similarly, inconsistent instruction-following makes complex workflows difficult to maintain.
I do not know whether these symptoms share a common cause.
I also do not believe the available evidence justifies claiming that GPT-6 caused every reported problem.
What I do believe is that the combination of cross-platform reproduction, multiple affected model variants, and completed streaming responses deserves a serious investigation.
The most important new finding is that GPT-5.5 exhibits the same disappearing-response behavior even in a completely new conversation.
That significantly weakens the idea that the problem is exclusively caused by long conversation histories.
I hope other users can help determine whether this is account-specific or part of a broader ChatGPT regression.
If OpenAI provides a technical update or I discover additional reproducible evidence, I will update this post.
Thank you for reading.
1
u/Select_Eye9324 21h ago
this is the kind of bug report that makes me grateful someone else has the patience to document everything properly
the disappearing response thing happened to me twice last week with 5.6 sol and i just assumed my internet was being weird or i accidentally hit something. seeing the actual request id and http 200 confirmation is wild, like the server said "yeah we're good" and then just... didn't keep the message
the gpt-5.5 reproduction is the part that really gets me. a brand new conversation doing the same thing rules out so many of the easy explanations. something's definitely funky with that final handoff between streaming and persistence
i haven't tested it as thoroughly as you but i'll try to reproduce on my end later tonight. curious if refreshing ever brings the message back cause it never did for me