I've been loving the game and it's improvements, (the last time I played this was when the standalone came out) but, in every server I've joined, without fail, I have had problems when placing objects in the vicinity and they either fall through the floor or outright despawn. It tends to be larger more important items like axes, shotguns, bomber jackets and MP5's...

I've seen a lot more items just disappear on me too such as, magazine clips, weapon attachments, tinned foods and lighters/matches. It's similar to the bug where you kill a zombie to close to a building or raised ledge and the fly off into the sky or float to the top off whatever they are near making them impossible to loot.