[BUG] After the release of Opus 4.1, the entire Claude 4 lineup stopped writing working code.

This happened immediately after the release of Opus 4.1. All code that the AI outputs is now practically non-functional. There are many errors, the AI doesn't follow prompts, makes fundamentally wrong decisions on its own, and breaks things that were working before.
This affected the entire Claude 4 lineup. Opus 4 and Sonnet 4 now also write non-working code, even though before the release of Opus 4.1 they wrote complex code with virtually no errors.