So me and a friend a friend were placing some stuff inside a small shed in the woods. Next day the shed was flodded with loot. Later we placed our tents (2 military) next to the shed and saved some stuff in it, along with some backbacks on the ground. The whole day everything was just fine and at the end of the day we decided to clear the shed and put all the loot in backpacks. We filled maybe 50 backpacks and placed them outside.
Next day: Everything (!) was gone. All backpacks, both tents and everything in it. Only our truck remained.

So i've already heared, that many players lost their tents at the moment it was placed or maybe some minutes later. But our tents last for at least 12 hours and after that not only the tents were gone, but also the loot in reach.