Did you lube insided of the case necks by any chance? It could be from the expander pushing down on a dry case neck. Lube inside the necks with a Q-Tip, or a pipe cleaner with a touch of lube on them.
Oh and what he said is correct those are not lube dents.
Also you might try backing the die off to touching the shell holder, and then back about an eight of a turn or so. If they are going back into the sme rifle that fired them it should not pose a problem. A lot of folks use the FL die to barely move the shoulder back, and close the neck enough to get bullet tension.
No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.