Whenever I scale armatures in blender and they have animations, the animations usually get messed up, this is because changing the scale of an armature doesn't change the scale of the animated bones, so if you make something large, the unscaled position keyframes on the bones still stays small, follow these to solve your problems:
- https://blender.stackexchange.com/questions/196995/applying-armature-scale-messes-up-the-action/197023#197023
- https://www.youtube.com/watch?v=QuY2-M_mVsA