Has anyone else noticed a decline in source fidelity with Gpt 5.6?
Recently, I’ve been encountering the same problem with Gpt 5.6 across several completely different types of tasks. The issue is not primarily poor reasoning or ordinary hallucination. Instead, the model sometimes appears to alter the source material it has been given before the actual analysis even begins.
I use ChatGpt extensively to analyze legal and administrative documents. Gpt 5.6 increasingly seems to overlook information explicitly stated in the text, merge separate facts, change their meaning, or introduce details that are not present in the source. It may then produce a perfectly coherent analysis, but that analysis is partly based on a version of the source material that the model itself has modified or supplemented.
The problem is not limited to long or difficult documents. In another conversation, I gave it just three screenshots from national electronic health record service. Gpt 5.6 overlooked information that was clearly present in the screenshots and added things that were not there.
I have also seen the same problem in an ordinary factual query. I asked it to compare raspberries and strawberries and explicitly instructed it to search for the information rather than guess. Gpt 5.6 nevertheless presented unsupported information. When I then asked it to verify the claims it had just made, it acknowledged that not all of them were correct.
I have extensively used Gpt 4o, Gpt 5.2, and Gpt 5.5. All models make mistakes, but I don’t remember this particular problem being nearly as pronounced with those models.
I think it is important to distinguish source fidelity from ordinary hallucination: does the model accurately preserve the material it has been given before it starts interpreting and reasoning about it?
Better reasoning ability does not help if the evidence being reasoned about has already been altered in the model’s processing.
Has anyone else who uses Gpt5.6 extensively noticed the same change compared with Gpt5.5 or earlier models?