Once you have successfully completed a dungeon with a group, you should be able to leave the party without receiving the ‘you hve joined too many parties recently’ disabler. That specific application of the mechanic makes no sense.
It should recognise that you completed the dungeon, ie are not trolling the lfg system, and allow you to join another dungeon group immediately.
I just completed 3 paths with same group of people, and got penalty for clicking leave group after we’d all said our farewells and others had started leaving. The player should not acquire that penalty in this circumstance for departing the group.