In the level of Cassandra's storyline I have to flee with a boat and let the other boat drift away. But when I finished all parts of the Level and bring my characters to the zone of the last boat, the match doesn't finish. They all stand there and I can just go on in the rounds. Any help?

From your description i think you released the secound boat.

Anyway, the Bug you described is known and can be worked around if you retreat from the exitpoint(worst case up to the secound boat) and then return to it. If this don't work you're one of the unlucky ones with a screwd save and you have to send your files to Creative Forge and ask them to fix your save. At least in the past they offered this kind of support but i don't know if the game is still supported.