There is some weird bug with the fog of war covering units when visiting quest huts. I did the following:
1) Sovereign enters witch hut #1 in "Wild goose chase" quest. I get the dialog and choose to continue quest.
2) I don't move the Sovereign after entering the hut. Instead I chose Janusk from the left sidebar and moved him two spaces.
3) Not sure if I had to press end turn to cause the bug, but after that or right after moving Janusk, my Sovereign was covered in fog of war and I couldn't see his surroundings. I can still choose him and move him around. When I move him the fog clears.