Rotation errors on squash and stretch rig from Blender to Unreal

Hey you mighty blenders,

I am struggling with a character that i rigged in Blender and then export to Unreal.
I have rotation errors when importing my animations from blender to Unreal. The animation is not completely wrong but some bones will flip and twitch very noticeably.

My first war a gimbal problem, however, wouldn’t there also be a gimbal in my blender animation?

I have tried to change the rotation orders
I have tried to change deformation bone parenting

But rotation errors persist when i import the rig.

What I would really like is a somewhere where I can read about the proper conventions for working between UE4 and Blender, I know a lot of add-ons are on the way but I would like to understand this and a node in the right direction would be hugely appreciated.

Cheers.MarcusBase_008.blend (3.9 MB)

Annotation 2020-03-23 234501 1 2 3

OK this is likely due to the fact that my rig has squash and stretch set up that does not translate well in unreal. In this video pierrick picaut explains another way to parent the deformation bones so that they are all directly parented under the root.

Of course it is not great later if i want procedural IKs but for cartoony animation it is perfect