Noticed this bug just recently. In cases where there is a concave domain, the wall distance was overestimated.
| |<...........>x | / ^ |_________ / : |/ : | : | : |____v_______
previously, the wall distance for the location x would be the nearest distance to a wall along any axis ( .. or : line). The proper wall distance should be the distance to a wall, regardless which axis this wall is on (/ line).
Not sure how efficient this method is, but it works and does not decrease the speed of the simulations considerably.