The explanation here is usually simpler. Any major change like this can lead to crashes. If I have three libraries, biz, bar, and bif, and each has bugs. You'v

The explanation here is usually simpler. Any major change like this can lead to crashes. If I have three libraries, biz, bar, and bif, and each has bugs. You've used biz. When the system was unstable, you'd debug until it works (either by finding the real bug, or by an innocuous change). If you switch libraries, the bugs which go away are the ones which aren't affecting you, since your software works. On the other hand, you have a whole new set of bugs. This comes up when upgrading libraries too. More bugs are usually fixed than introduced, but there's often a debug cycle.