Update: I should have added that the inner slid down just fine initially, and locked ok, but couldn't unlock without a tool. Yet all my other inners went in fine.
Here's something stranger. I was prepping for Nats this weekend and on a whim tried the inner because I hated to leave it behind. It fits fine now, both in the ball it locked up in (a HCF) and 5 others I tried. Weird..... I've seen and fought the swelling problem, this was completely different, like maybe some extra plastic on the tabs.... Maybe there was, I didn't see it, and it broke away.....