I am a big fan of Claude Opus as it has been very good at understanding feature requests and generally staying consistent with my codebase (completely written from scratch using Opus).
I've noticed recently that when I am using Opus at night (Eastern US), I am seeing it go down extreme rabbit holes on the same types of requests I am putting through on a regular basis. It is more likely to undertake refactors that break the code and then iterates on those errors in a sort of spiral. A request that would normally take 3-4 minutes will turn into a 10 minute adventure before I revert the changes, call out the mistake, and try again. It will happily admit the mistake, but the pattern seems to be consistent.
I haven't performed a like for like test and that would be interesting, but has anyone else noticed the same?