If you decide to do another version to fix the above bug, here are a couple of significant non-game-logic bugs. I'll leave it to your judgement whether they should be done right away or saved for the 5.1.1 patch that's apparently planned, but personally I think they're pretty important and I don't want them to get lost.
Clicking a tile with an evil eye overrides showing pressure plate/door connections, including if the eye is active:
http://forum.caravelgames.com/viewtopic.php?TopicID=40877
Obviously makes it hard to interpret rooms where evil eyes start on pressure plates. There are enough of these rooms that I think this is the bigger issue.
Asking a question without giving any answer options results in a Yes/No prompt that you can't undo from:
http://forum.caravelgames.com/viewtopic.php?TopicID=40896
This bug has less impact than the other one; the only published hold I know of that this affects is The Mining Business, and only on a question that you can avoid being asked entirely. But in my opinion, having any situation where undo doesn't work is a pretty serious problem.