Possible causes that have happened to me :-
1. The oil pressure sensor may be on the way out. Search out historic posts on this - there are cheaper than OEM readily available, but have to take care with the fitting threads.
2. When I had oil seeping from the rev sensor, I would get the eng Mgmnt light come on, sometimes when wet, & sometimes after a fuel stop. It would then go out. A smear of ThreeBond 1211 around the rev sensor's o-ring fixed that.
I'd guess there's a sensor or a connector to one somewhere in the the system that's playing up, intermittently. If you've Guzzidiag in your toolkit, or access to it, you could check the errors log. There might be something there which could point you in the right direction.