Sleeping state (as a CC effect and not self-caused hibernation) works in a bit different manner than stuns and interrupts.
It can be broken off by having damage taken (see Soothe
as an example).
For some reasons the resilience isn't applied when the CC effect is broken instead of fading off "naturally". Either it's a bug or something intended -- maybe they didn't want to punish a player too much for changing their mind and dealing damage.
(Poor wild striders with a Poison Spit
I wait for a first post or comment saying directly "bring back MoP" in the context of pet content.
Unless there's already one, I'd like to see it.