Reloading the 357mag

[Skinny Shooter]

I had loaded Winchester brass with no issues.
Picked up Remington brass cause that's all I could find.
Loaded up a new batch of loads with Win primers and HS-6 and Remmy brass.

After shooting the first set of loads this afternoon and looking at the primers they seemed to be seated deep.
Every load after that had one or two rounds that failed to fire and showed a light primer strike. They eventually did fire once I cycled them through again.

For some reason these primers were seated too deep.
I use the RCBS hand priming tool and don't think I seated them too heavily.
Anyone else have this problem?