I just did the beginning of the Thieves guild line, and man, did it glitch
spectacularly...
It started off normally; I had been given my instructions by Brynjolf, and told to let him know when i was ready. I wandered off to sell some random junk, got side tracked.... well, it was a couple of days later that I ended back up in Riften, in the middle of the night. Brynjolf was still waiting in his stall, in the empty marketplace. Oops.
I told him i was ready, and he started his "Gather round everyone" speech. Then we waited, while all the various merchants wandered in from wherever they go at night. I do the steal and switch, go back and talk to Brynjolf. None of the other merchants move (except Brand-Shei, who apparently went home again), so he gives me my congrats and tells me to go to the Ratway right in front of them all. Uh?
At this point a guard walks up to Brand-Shei's stall, and starts his arrest speech, then politely waits for Brand-Shei to come back again, walk all the way around him and stand behind the stall, before the rest of the 'scene' played through, ending with Brand -Shei being hauled off to jail (luckily I already did his quest, I doubt he'd give it to me now).
Brynjolf had already wandered off at this point, and it was early morning now. I headed down to the ratway, and just as i reach the Flagon, I pass him on his way back to the market place. Huh?
I go inside anyway, and the scripted conversation begins without him. Luckily, he came back, finished talking to whoever it was, and promptly left again.

So, I ended up following him back to the marketplace and his stall. Once there, Brynjolf, in broad daylight,
in full Thieves' Guild uniform, proceeded to give me orders to go around and collect the debts.
This was in front of all the other merchants, none of whom had moved since the previous night. And Brand-Shei was back. What?
All right. I go and do the protection money bit. Brynjolf is still in the stall. I talk to him, he tells me to follow him. I head down to the Flagon and wait. And wait. And wait. And head back up, where he's standing in the middle of the market, and doesn't start moving until I get there. Every time I ran ahead, he stopped. Instead of going through the Ratway, we went the back way through the graveyard, and down into the cistern. From there, the quests
finally proceeded as normal.
Amazingly, in spite of bending those scripts into knots, nothing broke. Dialogs continued, rewards were properly given. But damn, that whole thing was just utterly bizarre.
