Powell Machine on Youtube has several videos showing the lifter faces are not being machined correctly. Hardness on parts appears to be fine on the ones he has checked. Cam manufactures like to blame the oil, but that simply does not explain all of it as even people with mild cams have had issues that used to not occur in the past like they do today. Metalmax Mopar on Youtube also goes over this topic as well. Have to measure the crown numbers with a dial indicator on all the parts to weed out the bad ones.