I heard a while back Claude refused to attempt a task for days, saying it would take weeks of work. Eventually the user convinced it to try, and it one-shotted it in 30 seconds.
Totally true, also tokens seem to burn through much faster. More parallelism could explain some of it but where I could work on 3-5 projects at once on the max plan a month ago, I can't even get one to completion now on the same Opus model before the 5h session locks me up..