I have an armature generated with Rigify. I’m trying to export some animations I’ve made, but no matter what settings I’m using, result is always the same - in some frames random bones have weird rotation or scale problems after exporting to *.fbx. I tried baking action, but it made no difference at all. I even created a second armature specifically for baking animation/exporting, but problem still occurs. Baked or not - everything is ok until export. After that my animation is one, big mess. And yes, I checked armature scale, and it’s 1,1,1. Anyone have any idea what to do?
Post the file, I cant see your screen from where I live…
Cheers, Clock. 
Oh, sorry - you’re right. I forgot to post a file here. Here’s one, random, baked animation. As long, as it’s not exported it’s fine. After exporting it to fbx, some bones are stretching weirdly.
export_problem.blend (3.6 MB)