There is no 'stop' button on the playlist.
There is a 'continue' button, but nothing that allows me to stop loading the next encounter.
Instead, I have to load in, and then leave the playlist
You just be seeing a lot of extra loading on your servers.
-
I know this isn't the solution you're looking for, but going into the game menu and selecting "Change Character" is about the fastest way I've found to get out of the loop. I think Bungie envisioned it like a music playlist that automatically advances to the next track, I think it was meant to be a feature, not a bug; I get it, but that's not how I like to play. Anyway, "Change Character" then reselecting your main is a PITA, but it works. Might save you an iota of frustration down the line.