2007 Nissan Altima Shifting Problem

My automatic 2007 Nissan Altima has developed an intermittent problem when I go to shift it into park it won’t shift down past neutral. I can’t physically move the gear shift past neutral and can’t take my key out of the car. If I wait awhile or drive off somewhere else it will later allow me to shift normally again and won’t happen for awhile. It has happened maybe 8-9 times but I worry it will get worse or break the transmission. I’ve taken it to a mechanic and they looked at the transmission and didn’t see a problem but sense they couldn’t recreate the issue they couldn’t fix it. Any ideas?

I believe this is a CVT transmission, not sure a regular mechanic would be able to do much. Maybe time for a visit to the dealer.

I can’t believe I just typed that.