I kicked the statue (mad wizard ripping out pages) that swaps skills. I lost find weakness and gained fletchery at 100.
Now my skill list contains First Aid twice.
Wasn't that mentioned before somewhere? That the statue swapped one skill for another but left the original skill at 0 points? The staue designer said that it should be a straight swap and that it wasn't working properly. There was a bit of a debate about it being fairly harsh (you're a wizard with no concentration, necromancer with no necromancy etc)