same skeleton animations breaks on different skeletal meshes(that use the same skeleton)

i wonder if someone else had the same issue im having. im using the same skeleton on multiple characters, but in some of them, the heads ‘break’ (they flip in a weird axis) , this is really weird because when I retarget using their preview mesh is fine, but just -sharing animations they break. to fix this i had to make a retargetter from the skeleton to the same skeleton and create an aditional asset. if somone can shed some light on why this might be happening would be amazing, because duplicating every single animation for every character kinda defeats the purpose.
also, checking the meshes in a 3d software - the pivot axis seem consistent amongst the skeletons and meshes…