This bug refers to any and all tenacity type hunter pets. If you have a high level hunter, at least level 100, login and give this a shot. Make sure you can fly with a flying mount.
Go to any zone. Tame or use any tenacity type pet in the game you want. Call it out and continually mount on a flying mount, fly up causing the pet to disappear, and un-mount to make it re-appear. Rinse and repeat this technique. Do it like 10-15 times and look at your pet’s health. It will have lost a significant amount of health, taking “false damage” from… who knows what… This is a bug that should not happen. This does not happen with any other type of pet. Only tenacity. This will happen anytime the pet “disappears” or un-spawns from any means, besides dismissal.
I think it may have something to do with endurance training. I know for a fact that having the talent aspect of the beast makes this bug even harsher, since it directly effects endurance training. Only the pet takes false damage. The player’s health is never affected. Blizzard, please fix this bug. I want my spirit beasts to be strong again. Thank you.