Hi there!
I’m trying to export a character with a simple run animation (to be used in Unity), but for some reason the exported FBX looks completely broken compared to the viewport version in my blender file. If anyone has a clue as to what I’m doing wrong, I would greatly apreciate your advice! 
Broken animation looking like some kind of hilariously bizarre polka dance:
Animation as it should look:
Blender(2.79) file:
Animation Issues.blend (4.7 MB)