I am not sure if anyone reported this bug, but I know more people are suffering from this issue.
There was a convenient way until CTA 5.2 to move (and/or rotate) the 360 Head in Face Key Editor/Morph tab.
This changed in v.5.3. I could say it is the new feature of the software, but I do not think so, because the "Head 3D Move" and the "Head Rotate" icons are still available in the morph window. The original feature is very missing, because it was possible to move the head while the face elements such as eyes and brows were also moving by the same cursor movements.
Now, we have to use the gizmo separately in order to move the head. Its a big step back in the user interface.

Can you let us know, if it is a software bug, or this will be the new way of working in Face Key Editor. I hope, it's just a bug, that can be fixed easily.