drawing a N'Ty conga onto the poles to avoid running into more, I discovered that they stop at a certain point which they will not proceed beyond after which they cannot advance so you can get close to shoot them and they will take damage, all the way to zero health but they will not die and if you return to the other side of the line they will not follow you, they will stay on the line and remain where they are, see screeny which is that same situation https://steamcommunity.com/sharedfiles/filedetails/?id=2895542165