This probably has been posted here before but it seems that the connection lost to server/server crash happens when other deployable is put into ammo station. They are in the same space.
I just was just destroying ammo station (they are used now as barricades) with my knife when accidentally hit wrong button and put Proxy mine on it.
That probably crashed the server immediately.
And have heard it before from some folk this might be the cause of it but never tested it myself.