The achievement "Gone Fishin'" requires that you use a fishing rod on every under water drowned mob in the Hidden Depths DLC. The problem is I can't seem to use a fishing rod on a drowned necromancer. I have seen several reports of this online since the latest update as videos and comments from people before the update show you can clearly use the rod on a necromancer. But for now myself, my friends and several others can't seem to unlock the achievement due to this issue.