I just finished Raisu Palace with a PUG today, but as the loading screen appeared on the Imperial Sanctum, we got the "waiting for all players to load" message and a countdown timer. Well, I let the map load normally, with the countdown at zero for over half an hour I began to wonder... I heard some random dying noises in the background and some water-like ambience, but the loading screen didn't disappear, so I shut the client down and logged back in...
For my suprise, the Imperial Sanctum outpost hadn't been opened, and I asked around from the other PUG members and they had had the same problem too

I sent a mail to the support as normal so we'll see what they have to say about it. I wanted to post that pic as it's just so wrong... the Raisu Palace icon shows that the mission is completed but there's no imperial sanctum in sight