Since I read this thread, I've been trying to keep track of it.
It seems to be a problem with when you pick up a pet. I could be wrong, so maybe other people could watch for this? For example, if I pick up 1 pet, I get 9 total hunts, but if I pick up 2, I only get 8.
I think because it refreshes after you name the pet, it's counting that as a hunt, even though it's not.