Prior to this weeks patch, I had returned to the gave for a little under a month, in that time, I had only had a handful of issues with companions, and only died I believe twice due to the bug where your companion will either not follow you, or not have any interaction at all, which is deadly if you have your companion set to heal.
Fast forward to this week post-patch day, and I've died well over 12 times just doing heroics because all of the three current companions I have will randomly stop moving and casting anything at all. They won't respond to any skill uses, toggles between passive and active and the only ways I've found to get them working again is by dying, thereby forcing a respawn for them, or by dismissing them and summoning them again.
There are bugs that have been in the game for years, like the mouse sensitivity issue, which is astounding it's never been fixed, but this makes the game much much more difficult, and not in a fun challenging way. Hopefully it gets fixed, and soon.