wow, yeah looks like it's broke and the commit doesn't fix it either.
Here's canarys code, not ideal but looks like it works on TFS 1.4.2, give it a test.
src\map.cpp replace checkSightLine
bool Map::checkSightLine(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1, uint8_t z) const
{
if...