In the past I have asked that I be protected onto a later flight just in case I do not make my primary connection and I don't remember this every resulting in an problem.

Yesterday I did the same thing and when I checked my return flights today the remainder of my trip was gone. DM desk said since I was a no-show on my protected flight they canceled my trip. We finally got it sorted out (had to get a supervisor on the phone to re-clear my upgrades) but it was a PITA.

I don't remember ever having to cancel my secondary flight and it's never been an issue. Anyone else ever experience this?