Things are probably really rough over at Blizzard right now. Media is reporting lots of lay-offs (they’re calling it a bloodbath). Unclear how the HOTS team is being affected. If you’re losing your job (or your friends or co-workers), this hotfix isn’t probably going to be a priority unfortunately. Hope the employees aren’t having it too rough, and I wish the best for them.
That said, theoretically, I would think it’s not an OS issue, although I’m not a computer person. If it was an OS issue, then the older versions should have no problems, but from this thread it seems like it doesn’t matter if it’s an old OS or the most recent OS. Also if it was the OS, the problem would have started after an apple update, not after a patch update. So my guess is probably there is some programming glitch in the new patch.