Weird that it happens. The value is defined every time when you enter the big map.
Do you remember when you pressed the button to enter the big map?
I got the same thing by accident. I believe it happens if you save the game when in the big map, and then load the save. The game loads with you in the big map, without having the value defined.
Weird, the save icon should never appear during the big map section.
Just in case though I'll add a failstate for that, thanks.
