Hornady is doing its customers a disservice putting the 45 degree crimp ledge in auto caliber pistol seaters. You can clearly see the effects in the pic where the round is .479 below the crimp,Unfortunately it is not. Hornady
and that, as you found out, was the problem.
Buy a taper crimp only die and crimp in a second step, or buy another seater with a proper taper crimp built in.
The round should look something like this random round I photographed some time back.