Spoilerish bug:

I was doing the "Cecil's Mighty Staff" quest, and I completed it. To do that, I had to
kill a guy called Dietmar and his thugs.


That added an erroneous log entry for a DIFFERENT quest: "A Mysterious Murder": It mentions that
we followed an entry in Evelyn's diary, but met Dietmar and his thugs and had to kill them. Except that I have never read Evelyn's diary. I couldn't even get into her house.