Quest starts on a board near a tavern in Novigrad. You battle Vivaldi and he tells you to got battle that hostess in Passiflora. After you battle her she sends you to a "Sigi Reuven". But instead of updating the quest it completes. I looked into the guide and it said that you should battle Sigi and then someone else for a rare Gwent card.. Well this is not possible...

Please fix it..

I ran into this problem too. I was just doing the Gwent rounds cause I wanted more cards to build an elf deck. I got to the madam and I encountered that problem where it didn't give me the location of the next Gwent player.

Gwent isn't very well constructed. I only have a Temeria/North deck cause all the cards I have gained are of that branch. I would really like to play the Monster deck or Squirrel deck but lack the cards to build a deck of them. Why isn't there a vendor dedicated to selling Gwent cards in the Witcher world?

Having the same issue

Good news for everyone, just keep playing Witcher 3 and you will eventually meet Sigi Reuven, you can't miss him. Once you meet him you can play vs him, then the Quest will be active again!

I feel your pain on the Serenity not moving. To do the dijkstra quest. Walk into the room behind you if facing her > turn right into the next room > walk over to the tub > If all else fails just search this forum its how I found it out.

Still haven't found a way to play her. If you win the high rollers match can you still play her or will it fail the mission like a few quests have?

Actually haven't tried the High Rollers quest yet--didn't have a good enough deck, from what I gathered.

I'll try that and see if that fixes things and report back.

Same bug. I did not do the assassination of Radovid quest, as i did not want to take part in such a scheme. And it seems I can't talk to Serenity now.