d7c10b66d3
In MapgenV6::flowMud(), the previous implementation of coordinate inversion caused the 2 inverted mudflow iterations (out of the 3 iterations) to not loop over the area, so only 1 non-inverted iteration occurred. Fix this bug but only iterate mudflow twice, as mapgen v6 has only had 1 iteration for many years. There is now a good balance of 1 non-inverted iteration and 1 inverted iteration.