Animation disappears from character BP when compiled

What happens: I take the ThirdPersonCharacter BP, I replace it with a skeletal mesh based on SKM_Manny, no modification whatsoever aside from an added clothing piece, export that back to UE5.2, attach it to the TCP BP, it works, I hit compile, then it goes back to the A-pose.

If that wasn’t clear:
The default:


Before compiling:

After compiling:

The set-up for the skeletal mesh in Blender (I tried this on 3.1 and 3.5) is simple - I exported Manny, added the coat, parented it to root, added armature, transferred the weights, tested the pose. It’s a process I’ve used before in UE5.1 and it worked perfectly.

On import, UE was complaining about how some bones were missing from the import, despite the fact that I didn’t change anything.

Am I missing something?

edit: Video was bad. Replaced with screenshots.