Neuroshima Hex - other player can't see tile with effects

When I put a tile over a foundation tile, it turns semi-transparent for me, but my opponent cannot see it at all. When I remove the tile from foundation, he is able to see it once again. Then, when he moves the tile onto a foundation tile, it is the other way round - he can see the semi-transparent hex, but I see nothing! Same thing happens with other tile effects, like venom etc.: the player who switches the effect on is able to see the tile, while the other player sees nothing. We were trying to synchronize, both ways, and it didn’t solve the issue.