A rule is a nice thing. Because, if you know something, you dont need to calculate it. So you can save your time for something else.

BUT, there are “No rules without exceptions!”
I had a new idea how to figure out drawish positions in the endgame rook versus bishop. This type of endgame is a draw if the pawnstructure is symetric.

Like in this position

White can not improve his position. The black king is far enough away from his own pieces, so there is no risk to get exploded.

BUT, take a look on the next position

Whats up here? If you let Atomystica run with the rule implemented the program brings up a 0.00 evaluation. But if you remove the rule a checkmate in seven comes up! Here we have the exception. The bishop position is really bad here. Black can not avoid the rook sacrifice on a7 followed by the queen promotion of the a-pawn.