I just soloed level 38, I killed the boss legit, and there was a red box containing a body but of course it got stuck between the fence and little thing you stand on... Please fix this if it's possible?

Don't think its 'fixable' I don't know if they can alter the direction of the box.

What I mean by "'fix'" is by making an additional wall in front of it so it can not get stuck between the thin layer of the wall.

Again, not possible.

A. Wasn't in BOTS so not here

B. You'd have to edit models to do that and I don't think admins know how to do it without some bug. It would take a lot of time and only a little benefit would come out of it.

Bad luck, I'd say