2020-11-29: As there is an obvious work-around (duh!), re-classified the first issue as a “complication” instead of a bug.
The following issues were noted on Nov 21st, so they refer to the version installed with the November-20 hotfix.
Issue #1 (complication): Main System inaccessible from Cistern
Main System can no more be accessed through Cistern. The work-around is to first exit Cistern and form the group anew. The new group finder then allows access, if the group members satisfy the requirements.
Original text (reported as a bug):
With a group of 80+51+51, having just cleared Cistern, we attempted to enter Main System via the internal gate between Cistern and Main.
None of the group members were able to get into Main System; all got the new group finder UI when clicking the in-between gate, but the options for doing anything else except “Leave” were dimmed.
The Group Finder showed each person as “checked [X]” in The Cistern, i’m guessing that was the reason why the other options were not available.
Issue #2 (BUG): Loot options
In-dungeon (Cistern), we can not change loot options within a group entered through the new group finder.
Issue #3 (complication): Deserter debuffs
When entering purist Catacombs through the group finder, one person became stuck inside, at left wall at the entrance, after porting in and could not move. /stuck did not help, and /camp removed him from the group. After deciding to regroup, some of us left through the door (instead of using vote-for-retreat), and they got the Deserter debuff.
Because of these Deserter debuffs, we could not re-queue ourselves neither into Catacombs, nor to AOK.
==> IMO the Deserter debuffs should not be applied at all, in these 6-man dungeons.
Issue #4 (complication): Dungeons without resurrection pad
Cradle of Decay, Cistern, Catacombs, and Halls of Eternal Frost do not have a resurrection pad in-dungeon.
With the new group finder mechanics, dead players can no more use out-of-dungeon resurrection pads, as that would instantly remove them from the group, with no possibility to re-enter that instance.
Issue #5 (complication): Ongoing dungeons not enterable for new players
For the dungeons accessible through the new group finder, it seems that new players can not join ongoing dungeon groups. This could be rather inconvenient for long dungeons such as Black Castle and Main System, where players may need to leave early and/or be replaced.
Issue #6 (complication): Dungeon visibility
Higher-level purist dungeons are not visible for low-level characters. This would make it hard to join a dungeon just for the boss achievements, or even helping to form a purist group.
As a concrete use case, i actually finished my purist achievement by joining Black Castle at level 27 (being the only healer there); I’m guessing that this is no more possible with the current GF.
Issue #7 (complication): auto-kick of last player in a dungeon
When entering a dungeon (such as Cistern) in a private group, if others leave and you are the last remaining person in the group, you get the message “you need to join the group or you will be kicked from the playfield”, and get thrown out.
IMO, that is not at all needed (for any character) in these kinds of low-level dungeons.