Yup, the one where when you hit lvl 61+ you can only queue for an expansion’s starter dungeons. (Used to be 51 for the first 1½ years of DF).
I asked around, it’s not just me 
Please don’t take years to fix this again, you did it for DF, so you already know how.
Exactly the same thing happened to me. Queued up for a dungeon at lvl 60. Came out at 62 and now only have access to first 4 dungeons. Tried to open a ticket with Blizzard but that didn’t help. Really messes with the leveling experience.
Do you know if it’s at lvl 61 or 62 when this happens?
It’s at lvl 62 as far as I can tell.
I recommend locking at 61 latest if anyone wants to play in Chromie time and have some dungeons to do 