I purchased two RP 20-500's in late 2021. The following year I did my spring oil change and first used one of the 20-500's. While oiling the gasket of the filter for installation, I noticed that the base of the filter was completely covered by a real fine metallic dust. There is no doubt that it was metallic- easy to see and feel. At any rate, I cleaned the base the best that I could and installed the filter.
All was fine for the first couple of thousand miles, but then on an extended road trip around Alaska, I noticed that the engine oil pressure was down by 8-12 psi throughout the rpm range and regardless of whether the engine was cold or at operating temperature. There is very little, if any, help with automotive issues on many roads around the state, so I had no real choice but to continue the trip. All along I suspected the filter, as this was the only variable in my last oil change. As soon as I got home I dumped the oil and filter and planned on using my second RP filter for the fill-up. But I noticed that it too had the same fine metallic dust covering the base. I couldn't help but wonder what sort of dust or particles might be on the inside of the filter that I couldn't see. This, plus the fact that I didn't want to again experience what I expected to be some sort of a failure with the first filter, I decided to just take the loss and tossed it in the trash.
I completed the oil/filter change using a Fram XG2 and the oil pressure returned to normal and I haven't experienced a drop of oil pressure since. I have no doubt that something in the first 20-500 failed but I really don't know what (relief valve??). I am well aware that the RP filters are highly regarded among the fine folks on this forum, but I will not take a chance with them again as long as there are other viable options. It was probably just a lapse in quality control and just my luck to get not one, but two filters that slipped through the cracks.
Just my experience and of course, YMMV!