GPT 5.5 seems to be degraded

This absolutely is the case. I just renewed subscription and honestly I regret about it. Instruction following has became just terrible. E.g. mentioning harsh ETA for a feature long ago in the chat history somehow made model extrapolate it to the whole work, so it reflected upon itself, saying it implied it had been told to “rush things” (it never had been) It became viscous - it doesn’t prioritize the current focus and direct steering over the rest of the context. This is clear regression and it’s making it nearly impossible to deliver something of proper quality. Worth nothing that code quality itself has terribly degraded as well. Being communicated clear strict quality gates using native language features and align to the language BPs (in my case - nix), it just created a long messy bash script inside a nix derivation callback. No changes were made in configuration on my end to blame. No style changes in how I steer it. Please do something about it, OpenAI.