With the new patch 2.7.4.84161, the Uber Boss realm portals auto-close after completing them, allowing you to use 4 new machines to farm the materials without having to exit the game.
Just now, on the second round of opening portals, all of them worked except the Realm of Fright. The Realm Of Fright allowed you to port to the battle area, and the aspect was spawned, but it did not flag as a boss fight for my party to confirm. I killed the aspect but the two additional bosses did not spawn during the fight. The aspect also did not drop any loot. The portal remains open, but now there is nothing inside.