Yesterday while I was playing this map, at the boss wave I bought 2 hammers ( I was playing bezerker), so I dropped one at the ground and kept the other one.
Before the trader interval I dropped the hammer I was holding on a red couch next to an escalator , but it clipped though the couch and I couldn't use it anymore.

To the left of the waterfall is a small poster that players can jump onto from the potted plant next to it.
http://steamproxy.net/sharedfiles/filedetails/?id=843359380
Players standing on this poster can only be attacked by Husks and bosses, while close-range zeds simply roam around or gather near the escalators.
http://steamproxy.net/sharedfiles/filedetails/?id=843359919
I'd imagine that this is an easy fix. Just gotta make an invisible ramp ontop of the poster or something.

Hi, i upload your map on server and -> https://youtu.be/eMXHTl0qrbw
But solo game work on 100%
Why?