Happy new year and thank you for your reply! It's b) There are about 300 subpages and every link to these pages changes his colour after editing, except of three pages. The colour of these pages doesn't change ever and unfortunately, I still have no idea, why.
Hmmmm, well it could be a bit of incorrect HTML in there maybe?
Perhaps the easiest way to solve this would be to remove those three links, and add them again, if that's possible?
Removing the links and adding them again didn't work, unfortunately. You put me on the right track, though. I realised that there was, accidentally, at least one italicised letter in each of the relevant links and this seemed to be the problem. Thanks a lot!