Did somebody else notice that Prayer of Mending doesn't seem to work with pets?
I like to shield our tank and keep PoM active on him. Since in heroic scenarios sometimes our only tank is a hunter pet, I noticed that PoM doesn't seem to lose stacks and doesn't jump from the pet to anybody else, even if the pet gets damaged.
I don't know if PoM can jump from a real player to a pet, but if it does, I can also imagine PoM getting stuck then.