Have 0.38, ran into a bug with the fishing in quests 17 and 21. I have caught 6 Icarius all after I got the quest and none of them have triggered the flag for it so I can't proceed. It is now also the only fish that I can catch (I caught 5 in a row) and so I can't catch the fish necessary for quest 21 to progress that one either.
Viewing post in Knightly Passions [1.60 version] 18+ comments
I actually figured it out. There is still the issue of the Icarius being the only fish I could catch at the Lake when the quest is active. However I caught one at the river behind the fisherman's house and it progressed. I couldn't find the fishing location previously as the area to click on was very small (maybe expand the button to include the river as well). I think the confusion came from the quest name being "The Forest Lake", which makes you think that you are supposed to catch the fish at the forest Lake, a clearer quest instruction in the journal could also help.