This isn't handwaving. I'm talking about bugs in the software (not hardware) with rdars attached. For some of them the bug dates back to like 10.5 or so, and the fix is straightforward, but it just hasn't been done. For others the problem is harder (but still possible) to reproduce, but the buggy component is managed by what has been described to me as "one of the somewhat less competent teams" at Apple.

Describing them in more detail will deanonymize me so I'm not going to do that.