Not for me - ALL my G1000 knobs behave the same way including the PFD FMS knob. Also note that one of the default mouse RMB bindings is to “COCKPIT INTERACTION - SECONDARY ACTION” so I suspect that this may be intentional behavior, and it’s possible that the PFD FMS function is bugged for you.
I suspect that quite a few current issues would prove to be intentional behaviour if we had access to more definitive information. It’s possible that some or all of this info is available in the SDK docs - I haven’t waded through them to that degree. I did search on a few likely keywords and got lots of hits but any I examined were related to internal engine stuff, I found nothing that a sim pilot would find useful.
As I said before, we need proper user level doco…