Hey Alex,
Yes, UsePawnControlRotation is meant to control the Camera rotation. But when you’ve got the Camera attached to the Mesh with “Parent Socket” set to “head”, it causes a conflict. If you want it to inherit only the location of the head bone for the camera, you’ll want to use set location or another setup. UsePawnControlRotation doesn’t override attachment.
If I simply disconnect all of the logic that modifies the head rotation and use nothing but “Use Pawn Control Rotation”, then it has the same behavior without the jitter.
If you need the head bone to continue to rotate for MP purposes so other players see the head rotate, I’d suggest either A) Creating a separate head bone that controls the camera or B) Attach the camera to the head bone differently (Set location…something like that). Try unchecking “Use Pawn Control Rotation” and see what’s happening. The head bone is trying to do that on top of the Pawn Control Rotation.
If you want to send a 4.13 version of the project, we can take a look and see if there really is something wrong, but so far it seems like it was working by accident in older versions or a bug was fixed that actually shows the error in this setup. I.E. “Use Pawn Control Rotation” may have been overriding attachment rotations when it wasn’t supposed to.
PS - Concerning the delay in response, we just had a huge change in our process over the last couple weeks and it has created a bit of a backlog. We are working on catching up and will hopefully be more responsive going forward.