> made a change that seemed right at first glance, maybe even passed code review, but fell apart completely when it came time to build on top of it

Maybe I'm not understanding you're point, but this is the kind of thing that happens in software teams all the time and is one of those "that's why they call it work" realities of the job.

If something "seems right/passed review/fell apart" then that's the reviewer's fault right? Which happens, all the time! Reviewers tend to fall back to tropes and "is there tests ok great" and whatever their hobbyhorses tend to be, ignoring others. It's ok because "at least it's getting reviewed" and the sausage gets made.

If AI slashed the amount of time to get a solution past review, it buys you time to retroactively fix too, and a good attitude when you tell it that PR 1234 is why we're in this mess.