Fill up after party member leaving

[ReliReliance]

Hey,

is there any good reason fill up is not automatic once someone leaves the party mid dungeon?
Or that it is not available to everyone and not only the random party leader?

I just had a run of castrum (msq) someone left right at the beginning and the person that was randomly selected as party leader didnt know how to fill up.

Thanks

[Rongway]

is there any good reason fill up is not automatic once someone leaves the party mid dungeon?

If the party decides they just want to abandon the duty before all the vacancies fill, they don't want you pulling in people from their half hour queues just to abandon after they join and make them sit through a whole nother queue again.