The key issue is that their post-mortem never explained what went wrong on two out of three issues.

All I know is that my requests can now travel along three completely different code paths, each on its own stack and tuned differently. Those optimizations can flip overnight, independent of any model-version bump—so whatever worked yesterday may already be broken today.

I really don't get the praise that they are getting for this postmortem, it only made me more annoyed.