I had the same issue when creating a breakable skylight that I wanted guards to walk over. When they refused to walk over a destroyable mesh, I tried putting an invisible, movable cover on top (that would move when the skylight was broken). Still no luck. If I solve that problem I will post here.
I had the guards move to me while I was directly opposite the moveable mesh and they would walk the long way around it to get to me.
No luck with putting path nodes on a moveable brush either.
I did have a moving grind rail that guards would use occasionally.