Old thread but I had the same issue and poked around in code to dig up the cause (in my case, anyway). In case someone stumbles upon this - I suspect the issue is the “control rotation” (driven by PlayerController) fighting your character BP for which is actually setting the actor’s rotation.
By default this setting is true, which causes some code to update the character rotation (which is subsequently stomped on by your character BP). Untick this box and you’ll likely be good to go.
