I don't know whether the side quest "A Girl Won in a Card Game" is supposed to show up in the "Assassin" storyline. For me, it did. I'd been playing dice against a few people in taverns, then one of them gave the usual preamble which leads to the quest. The first time, this was the result: Log files are attached. As it happened, I had a saved game from just outside the tavern where this happened, so I reloaded, went in again, talked to the same guy again, he challenged me to play for the girl again, and this time he showed up correctly in the room. The game went according to plan and I got the girl. Then I went downstairs and challenged him again, and he played again, which is not what usually happens - normally he only offers the girl if you're already beaten him to the point where previous gamblers refused to continue any more. This time he not only played again, he had a lot of money, more than any previous gambler - I took several lots of 500 gold off him. After that I took the girl to Martinique where the quest played out to completion as normal.