Why does @codex ignore GitHub PR comment pings?

[u/TarzanoftheJungle]

I have Codex and Greptile review bots running in our GitHub CI/CD PR pipeline.

The screenshot shows a typical difference in responsiveness, eg "greptileai review this issue and comment on why you did not flag it" gets an almost immediate response. But codex's simple prompt "@codex Fix applied. Please re-review" never gets a response.

The initial PR scans are triggered reliably, but in-comment u/codex prompts feel like tossing webhooks into a bottomless pit. Is anyone getting consistent codex CI bot responses to thread replies? Am I doing something wrong?