As for auto-deselecting, the issue you're describing is definitely a bug, because there is no minimum distance for auto-deselecting, and the threshold is 180px, so the distance shouldn't be that short.
As for the range problem, honestly, at this point, I'm just going to add a Range Description section to the info page to clarify it. Since I'm using ScriptableObjects to store each monster's data, it should be very easy to add.