There is no guarantee that this will be fixed in 4.15 if I can’t get the necessary info to enter a bug report. Can you attach the fbx for the skeletal mesh and animation that you’re attempting to import? If you’d like it to stay private, you can PM me a download link on the forums.
You can try 4.15 now if you want, but it likely won’t be fixed since we never had a bug report for it.