It sounds like your bypass is not working properly or has a really stiff spring in it. It shouldn't have anything to do with lowering your idle pressure as the engine warms up. It's purpose is to open only above a certain psi level (cold or hot engine) which the engine usually hits on a cold start or at high revs. The high pressure won't hurt your engine but it can contribute to some leaks or possibly even rupturing a cheap filter = if the throttle is winged after a cold start up - and I would use a good quality
oil filter like a Wix.