Take the pump off and remove the bypass plug and valve to see if it is sticking when being moved under pressure by removing the spring and use a small magnet to put in the spring hole in the valve and see if it slides in and out real easy
in the top cover
New motors make metal and all the oil in the motor goes through the pump before it goes through the oil filter, hence the tiny bits of metal possibly making the bypass valve sticky
I've had that happen more than once and others on here also have had that
Good luck, please let us know what you find and what it took to fix it