If it has happened twice to you, then there's a decent chance that you may be doing something wrong, or that something else is wrong with your equipment. I can't really imagine what that might be, though. Don't know for sure. But the odds of getting two bad dies is pretty small. You don't have a black cloud overhead following you around, do you? Or recently return from Louisiana after insulting a voodoo witchdoctor, did you. LOL
It would be nice of someone with a lot of experience with the Lee collet die could watch how you set it up just to make certain it's not something you may be doing unknowingly to cause the problem. But, as small as the odds are that you got two bad dies in a row ...... it is possible. And, you are describing the correct set up procedure as I remember it to be.