Well, i never changed the names of my cubes in JPM, and i haven't this trouble with my other mobs (chicken, pig, ocelot and sheep) maybe i need to rework them to avoid any problems in the futur
But for the wing bat, my jpm use plane and not cube. So the only part used in the jpm file for the wing is called PlaneX33
So i don't really know what to do :/
Look in "bat_head.jpm", there are many duplicate IDs.