It's not unknown for LEE dies to be out of (their own) specs.
Do you think the expanding plug is going all the way in the case? If yes, contact LEE.
If not, would it help to trim the die a little (top or bottom), and either allow the top plug to screw an extra thread or the case to get in further?
I don't need FCD with LEE's 45 dies, or any other caliber, but I did have shavings in 45 at some point:
The crimp would close on the cylindrical part of a new bullet, and simply screwing the seating plug 1/2 turn solved the problem. The crimp now closes on a slimmer part of the bullet.
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