Fog of War acting like a barrier

Mythrialus

In the original BG, if there is a small sliver of the blacked-out "fog of war" between two previous explored areas, the party would walk through the "fog" and go to their destination taking the most direct path. Now, if there is a small piece of the blacked out area, the characters will walk all the way around town instead of just through the small, blacked-out area. Is there a way to fix this????