I used to tumble lube with Lee Liquid Alox and found that my set C.O.A.L. was changing.
The reason turned out to be a build up of the Alox on the seating die.
When I took the die apart to check it out...wow!...lots of build up in there.
I do not tumble lube any more but do have a bunch of cast bullets that I tumble lubed.
Now, when I use them I drag the bullet tip across a paper towel to remove the Alox on the flat bullet tip and then seat the bullet.