I finished "Blindsighted" for the Thieves Guild, and before doing "Darkness Returns" I powered through all of Vex and Delvin's side quests. I got all four merchants and special quests, however after completing the final special quest, "Under New Management" never showed up.
After that I finished "Darkness Returns" (and got the achievement), fast traveled to the Cistern, talked to Brynolf (he gave me his congratulatory spiel, even called me guild master), but still no "Under New Management" quest. Talking to Delvin or Vex only yields their standard dialogue for getting side jobs. I tried console-commanding the quest to start (I did
setstage tgleadership 0, 10, 40 and 200) but all it says in the console is
getstage >> 10 and nothing changes.
I've checked the quest log and "Imitation Amnesty," "Silver Lining," "Summerset Shadows" and "The Dainty Sload" are all under the completed section. I have no running side Thieves Guild quests either.
How do I start "Under New Management?"