My son had his 2015 Duramax 6.6L 99,xxx miles oil changed at a shop and they used a CQ red oil filter. My son drove the truck 20 miles and when he started the truck up the next time it had a very loud knock. Extremely loud and the truck had around 30 psi oil pressure according to the gauge. I went and bought a AC Delco filter and changed filters and oil pressure is back up to between 60-70psi. Sent the CQ filter off to Mann for testing and they say no defects found in the filter. Thoughts as to what could have happened?