IMHO, you have a bad batch of primers. If you had headspace issues, you wouldn't have such deep strikes.
I recently bought a bunch of primers ($20/box) at a yard sale. Same thing happened. They were at least 25 years old but that has never been an issue before. Some went bang, some didn't.
I tried some from each brick in primed only cases. All were the same. Some went bang, some didn't. Primers looked just like yours, well struck.
I normally won't buy components at a garage sale for just this reason.
All of the bricks looked as new. No water stains, no corrosion on any of the primers. All bright and shiney.
The only thing I can pin it to is poor storage or manufacturing faults.
I threw all 5 bricks away. They reside in the landfill.
This happens, especially if they get to hot. Same thing will happen to older double based powders.
Just pull the bullets in what you have, pop out the primers, soak the all in varsol and dump them in the garbage.
I use those same primers. They are very consistent and work well at all temperatures.