Well, that sounds like a mistake on his part.
Any new flat tappet cam, needs to start up instantly, and be held above idle speed, about 2000 rpm to run-in the cam lifter surfaces.
Any idling is a no-no.
Sounds like he needs to do some more study on current aftermarket flat tappet cams, and the necessary procedures.
I would reassess the pushrod rotation while the engine is running, as a start.
A sample of
oil for analysis is a good idea.
Gary