Unreal should have an option to rename the bones on your rig if they are not the right names, Unreal is effective, but its not efficient. But at the moment all we can do is only match up the bone names which is not enough, if the bone name is wrong on our rig you want to beable to rename the bone instead of having to do it in another a 3d modeling program… You should beable to see the effects of this bone distortion bug of Blender when you go into the skeleton editor upon importing the skel mesh. The Armature bone rotation bug I think gets triggered off in Blender when you move or rotate any of the bones when in the Object mode instead of in the edit mode and you won’t notice any change to the bones except if you look at the bone scaling, the bone scaling change will show up in those numbers. But the armature will all look perfectly fine in Blender… But soon as you import it into Unreal, and you didn’t set the scaling back to 1 the scaling change will show up in Unreal, usually when doing the retargetting or or when you look at the bone hierachy in the Skeleton Editor the distortion will then show up and if the bones look all warped and twisted out of place then that’s the rotation bug.