I went to the Mews, freed the nobles, closed the portal, spoke to Verandis Ravenwatch, he told me to go speak to King Emeric, the quest updated to show that.
I left the Mews… and the quest changed back to “Talk to Vetandis Ravenwatch”. Which is now impossible because I cannot go back into the Mews.
When I googled for a solution it seems that people still regularly get different bugs with this quest after eight years. I mean, really? I guess I’ll have to abandon the quest and do it again and hope it doesn’t bug out again.