Hi,
I am not too sure I understand your setup. Could you pm me with this prefab so I can study it and see how it is understood by my system and photon.
In all cases, for such rig, I would encourage that you only have one fsm responsible for synching variable, it's totally fine to outsource networking synchronization, especially within the same rig. Then you end up with only one photon view, which is better for performances, one fsm with synched variable, which is also better for bandwidths, and your turret would simply get and set its rotation on that fsm that is not on the same object, but in its parent.
in all cases, I am willing to get to the bottom of your issue, as this shoudl work and not fire any nonsense, so if you can share your prefab, that would be great.
bye,
Jean