My issue looks the same. I have a unit controlled by AIController and when I command to shoot the enemy that above or below my unit, controller rotates pawn capsule instead of using AnimBlueprint and rotate only hands. It looks like characted walking 45 deg rotated to sky or to the earth. I cannot find how to correct it. I can share my Aim / Anim and BP.
I do not care if it is BluePrint or C++.
I use BP for preview and then converting what makes sence to C++
Thanks