They disabled the above-listed functionality for all zones except the Maw. Currently they don’t want people using the group finder to abandon their f-ups in the Maw either (apparently). Return to Oribos and zone back into the Maw to group properly.
https://us.forums.blizzard.com/en/wow/t/grouping-in-the-shadowlands/736070
Really, Perdition Hold isn’t even that far from Ve’nari’s Refuge.