alt Hacker NewsSimilar usage here. But I encountered this moments, and I chalk it up to the random nature of LLMs. Back in Sonnet 3.5 days, it would happen every other day. I even build an 'you are absolutely right' tracker back then to measure it. Opus 4.6, maybe once or twice a month.
Yes, subjectively there do seem to be moments where the quality of the output drops significantly - usually during US peak hours.