Animations squiggles

My animations look like spaghetti. Arms are all twisted up. I copied the exact skeleton from UE4. I imported, transferred meshes from MAYA LT and they still look like this:
With animation :

without:

as you can see, when I have an animation on the character, it turns to spaghetti. I tried the whole switch the bones from skeleton to animation only and vice versa, even mixed them up. Idk :confused: