hi, it was happening to me as well, my vending machines keep disappearing as soon as the game start before the game start everything was fine.
1 - If possible try moving whatever you have in that disappearing spot, that was my 1st fix and it worked i moved my vending machines somewhere else.
2 - after that it seems other stuff was randomly disappearing all over the map as well my map is huge and little stuff that i couldn't keep track of what was getting lost.
everything seems to get fix when i double check all my map settings for example, when eliminated drop items and on team settings i had it as keep. ( i know it sounds like it doesn't make sense but just double check them or reset all settings to see if its fix. Good luck.