Okay the oil filter is acting as an accumulator. At idle the oil is shooting basically straight up to the main Passage. At the same time it's backing oil into the oil filter from the line coming out of the oil filter not the line going into the oil filter. Now the engine gets revved, the oil pressure is still going up the passage but we must remember the passage is Step drilled so it is a restriction and the excess oil is being fed through the out line of rhe oil filter, to the oil filter backwards building up pressure in the filter with the air behind it. We then rev the motor, the oil pressure hits the 70-pound marker or the 80 lb mark and the filter is now charged with 80 lb of pressure. We let off the throttle, come to a stop at the stop sign, the oil pressure going up into the motor at this time is trying to maintain about 35 lb of pressure however the accumulator effect of the oil filter is now pushing the oil back out of the filter into the passages and is causing the oil pump to stop sending oil up here. The pump goes into bypass the accumulator finishs dumping off to 35 lb so that the pump can start pumping again into the passages backfilling the accumulator oil filter and pushing oil up through the step drill passage to the top of the motor. We accelerate again the oil pressure builds. The accumulator fills with 70 of pressure. We come to another stop sign or stop light engine RPM drops oil pressure drops. The accumulator starts pushing oil back into the passage the oil pump says too much pressure going to bypass and it goes into bypass until the accumulator and the pump are at an equal pressure again.
Does this make sense or am I just nuts you must remember I am old.