I agree with Mike's assessment. I've over-cooked brass a few times while searching for the right setting on my induction annealer and I experienced the same problems as you.
If you want to 'test' the potential problem and solution, run a couple of pieces of brass into your sizing die with the expander ball in place. Run the case up to fully size the neck and far enough down to clear the expander - do this five or six times to work harden the brass a bit. If over-annealing is the problem, this exercise should improve the condition of the brass to the point where you can deburr and load normally.
