[Mobhack]

There are bound to be rounding differences, in "edge" conditions.

Try left clicking the map a few times to make your unit "look again" in that direction, if you should see this. Each "look" will respin the LOS calculation.

Also - if you have fired weapons at/near the target and e.g. had near-miss splashes in the area, then there is the possibility that some partial smoke will be generated in the hex, but insufficient smoke points to justify a partial smoke icon, but sufficient obscuration in that hex to now just tip the LOS penetration algorithm.

Cheers
Andy