I saw that adding more support for scaled skeletal meshes was on the roadmap, so I figured I’d mention this: If you use a scaled skeletal mesh (presumably, a scaled root bone), root motion is not scaled accordingly when extracted.
e.g. I have my skeletal mesh scaled to 12 on export. When I enable root motion translation in my Montages, the animation itself has the root motion properly extracted, but the motion that’s applied to the capsule is only 1/12th of what it’s supposed to be; or, more specifically, the root motion is applied as though the mesh were unscaled (i.e. 1/12th of it’s original size).
This can be worked around by scaling the size of the root motion keyframes before exporting, though it causes weirdness when blending montages out; since the non-root-motion version of the anim has the skeleton flying around huge distances, when the montage blends out and Unreal reduces the amount of root motion being applied (and blends back to Actual Animation without applying it to the capsule), the animation is trying to blend into this exaggerated motion and sometimes produces weird results.