Frozen fbx animation on import

Occasionally when I import animation into UE5 the animation will appear to be frozen on the first frame, like it is not reading any other keys. This is in the context of importing many other animation clips which all import fine; about 1 in 40 imports are frozen. They were all exported / imported with the same settings, and the frozen clips look fine / have animation when inspected in other DCCs. Has anyone seen this before? This is going from Houdini->Unreal.