TC war - my opponent can see my repairing villagers, but I can't see theirs. Why?

I just played a game of team game African Clearing, and as often happens, my town center happened to be directly next to the town center of one of my opponents. In the TC war though, the line of sight of my opponent's town center allowed them to see my repairing villagers and target them, while the line of sight of my TC didn't allow me to see the repairing villagers of my opponents. This caused me to lose the game. A comparison picture is at https://imgur.com/a/ZlYscUi - top is my opponent's line of sight, bottom is mine.

Does anyone know why? Especially considering that the positions of the repairing villagers are symmetrical, I can't figure out why my opponent has line of sight on my villagers I but I don't have line of sight on theirs. The only guess I have is that it has something to do with the line of sight radius not being calculated with the middle of the building as its origin? My opponents allied civs were Indians, Poles and Japanese. We were both Berbers.

There are no outposts or other building off screen that would give my opponent additional line of sight to the position of my repairing villager.