[AnthonyG]

Maybe your baffle didn't get put back during rebuild. It would seem all indications are the pump is working while seeing oil. Hard stops without baffle as oil pan is much longer than wide could let enough oil move forward to expose pickup. Possibly turns let oil pickup remain in enough oil to get reading. Not sure but worth a try to get a flex scope cam to look inside oil pan to see if you can see a baffle. Or the painful obvious is to remove oil pan.