I kinda thought maybe that was the culprit. I have some once fired Hornady brass to try as well. Someday hopefully I'll be able to get some lapua whenever it comes out.I’ve experienced the same early pressure signs at modest velocity. Stiff bolt lift, ejector marks in my 28 Nosler. I went home and pulled between 15 and 30 bullets. Then loaded a new series with a different powder only to have the same issues. I did this 3 times and finally realized it was the Nosler brand brass.
Switched to Peterson brass and never had another problem.