Peninsular low oil pressure

[ArmyFish]

I have a 1996 Penisular Diesel with ~ 1000 hours and a low oil pressure issue. I bought it a few months ago and have been running it to test it out. It runs perfectly smooth without any strange noises on Rotella SAE 40 oil. I’m looking to see if anyone has had the same issue and if there are fixes or info? Cold start up reading is about 30 psi. Operating warm about 2900 rpm it reads about 20 psi. When I throttle down to idle with the engine warm it drops below 5psi and jumps back up when I give it some throttle. I confirmed the gauge readings are correct with a mechanical gauge. I also installed a digital auto meter gauge to find out how low the pressure was dropping. The engine moves the boat easily to 19 knots at 2900 rpm. I received excellent results when I did oil analysis. No indication of bearing wear. I’m about to replace the oil bypass valve and the plug next to it if I can get to it with engine in boat.

[hp4570]

My Peninsular does the same thing after running for a bit. I just keep the RPM over 11-1200 for a few minutes until the engine temp drops. My oil pressure is a steady 50 psi even when running, even when the engine temp is 180'ish though.