Yes I know about the bushes but I don't see any bush blocking them :). Moreover it blocks only marksmans, the other troops go through. I'll try to reproduce and send a screen. Maybe there is an invisible bush.
If skill wich slows down gunmen is active then at the moment of bush appearance gunmen will be blocked on the one point. I will fixed it in the next build.
Also what do you think about this skill? Is it useful? It slowdowns gunmen if there is no swordmen in front of them.