In some cases, yes. More frequently this sort of thing has been performance issues (comment reading something like "don't do X here, or else it interacts with

In some cases, yes. More frequently this sort of thing has been performance issues (comment reading something like "don't do X here, or else it interacts with Y in a way that kills performance of the whole application"). Testing for performance regressions can catch stuff like this, but since that's not typically done for every commit, you can end up having to do significant forensics or trawl through hundreds of commits to find the cause.