I experimented using the feeler gauge to get the extra bump and that work for some of the batch I was having trouble with.
But next I backed out the decapper to see if it was pulling the shoulder back out when the brass is pulled out.
I at first didn't pull it completely out, I wanted to see where I could set it at its highest point and still get the neck sized properly.
It was then while: adjust decapper up then size, I noticed at one point some resistance. Felt like sizing. And lo and behold checked the headspace and got the bump I needed.
Sized the remainder of the "bad" batch and they all turned out fine.
The Dillon decapper assembly can be used as a stuck-in-the-die brass remover by screwing the assembly down into the die.
I'm thinking my die left the factory at a setting where for some reason the decapper was low for some brass and i was actually pushing the flash hole against the bulge that would push a stuck case out.
At least that's my guess.
Next stop trimming (and another question about that for another thread)
Thanks again for the help.