I just noticed some strange display bug, or counting bug for collectibles.
As you can see, I have 100% and all sub-achievements completed in Bolyinthia,
although it shows 3 quests not completed.
I did a lot quests and some quests repeatedly so I did not keep track initially, but it seems that some quests
did not count properly.
I remember this happened in other zones as well, like Ystra and Elven Island.
Can you check if there are issues witht the quests, or is this just a display bug ?
As for the bosses, I killed several times, but there seems to be no issue.