Woah, larger issue. Way larger and tested and confirmed (for my world at least) Some gaia mobs (have not tested all) will not lower your heart count from HQM when you are killed by them.
Not all of them, having tested a few more some seem to and some do not. odd.
Also seems like I sometimes retain my exp when killed by mobs that do not make me lose a life. I would be willing to bet that the mobs that do not make me lose a life are also the ones who do not allow me to drop a gravestone. Can someone else test on the mobs from the common forrest to see if they can replicate any of this?