[ozo]

I had a similar problem last year with mine....and can't remember
what I determined caused it...DUH !!!!!
I did take it apart and clean it really well [shuttle arm sticking]
I don't know what could be misaligned and mine had me pulling
out my hair....but after I put it all back, it has been fine.
As far as the primers flipping, that is most likely caused by
returning the handle upright too fast.
If cleaning and re-assembly doesn't fix you up...call Dillon.
Their customer service will dance you right thru it.

Tip:
Keep a toothbrush, or equivalent, handy.
Clean the primer anvil and the shellplate area often.
If you use fired brass, you get old powder funking it up.
It can even dent your primers when you seat them.

Shellplate not turning.....is the bolt too tight?
It must be backed out 1/4 turn, although I do mine
by the feel of it....and when set, tighten the set screw,
snug only, to hold the bolt. If not, the bolt will move
as you turn the shellplate.
[provided nothing is caught under it, like a primer]