This is very noteworthy, because the bot's get's stuck under it untill they die!
It's very easily recreatable as shown here. (Includes stuck bot)
an easy fix would be to add a brush to the catwalk stoping you from mounting the zipline.
As you can see, My teamate is still attached even tho I've been knocked out of my ult. I could not drop them and had to wait for the timer before they got released.