Then the problem is with you. You wrote code that had a dependency on a specific non-guaranteed feature (the bug) and then feel jilted b/c they changed the non-guaranteed feature. What you should have done was written defensive code and tests around the NGF so that when it changed, your tests would catch that and either not upgrade or allow you the chance to fix it.

I don’t feel any negative feelings towards the library developers. I have my versions locked so these unexpected surprises don’t happen. In this case it would have been extremely difficult for me to have noticed that the behaviour seen was not intended and supported by the developers.

My point is not that this is an unsolvable problem, but that it’s not a good idea to go “semver says this is non breaking, let’s just chuck it in production”