If the tip is not fully seated it will cause the jamming problem. As the tips age they seem to get a bit brittle and not remain tight on the tube. Soetimes a tiny split develops. Just call Dillon, they will send you some new ones.
I store my tubes with an AR 15 gas tube cleaner (long pipe cleaner) inserted into them. That keeps them clean and free of tiny little crawling/flying things.
Blackfoot