After upgrading Claude Code, encountering intelligence decline issues with third-party models. The symptoms are: 1. Clearly no typo errors, but it prompts typo errors; two words are identical, and if unresolved, it will randomly rename them. 2. Over time, it forgets the tool used to update files and keeps trying to edit files with sed, but complex matching with sed can't handle it, so it can't be fixed. It seems there are no problems if you don't upgrade.