Strange bugs in Chapter 2. (The Witcher)

In General, many additional tasks are performed by themselves. Well, as performed. The reward I get, and in a list they do not fall (there are exceptions). For example, I wanted to talk to Vincent a Mace, and he said to me, saying I brought him all three heads and gives you a rune, though neither a swamp or on an island Wyverns, I wasn't even. Then wanted to fight with the Oil Bob, but I didn't manage to hit him as already defeated. Etc Maybe we should head first to start?