> 30 minutes of patient, old school troubleshooting

This is also the best way to understand a codebase, and it's quite enjoyable.

I think the models are getting too egotistical. They're so confident of their fixes they won't bother suggesting basic techniques like isolation of the problem by disabling code paths, for example. They'll keep shotgunning less-and-less likely fixes with undiminishing confidence until the code is full of fixes that do nothing. Then they'll double down on why these should be kept.