I would say I have encountered that missing inventory bug more than often. 1) Always ensure you have more than enough space for the weapons that you are gonna put inside your bag otherwise your weapons will not drop, it will just *POOF* disappear. Common bug in my playing journey. Always check how much space your friend has if you want to transfer something to his bag. If there is 0 available slots, anything that you transfer = disappear. So do a double tally, check it on your side and then have him check it again before any attempts to transfer stuff to bag. 1b) Many times ITEM will sink beneath the ground/surface, you can try to point your mouse around until you see the "GEAR" icon and try to pick the items back up. Yea one of the buggy moments again. 2) The teleporting scene you just witness could be someone that ALT-F4 ( very common if you read the forum enough ) to escape being seriously wounded by you, join another server and move back on his/her location so they could heal up, position themselves behind you and then take you on by surprise. I hope I have simplified it enough for you. PS: If it wasn't bad enough, I have lost a full character numerous time for no reason. I merely restarted the game when memory starts to leak so badly that fps climbs to a halt to come back to a "Please choose your gender". Lost quite a few good stuff, Nvg, Gps, Coyote Backpack, L85A2 AWS but hey I am not gonna flood you with " Hey It's Alpha " but lets be honest, IT IS really alpha and there's quite a few bugs that I am really hoping the dev would fix in the coming future but meanwhile lets play the game with a casual mindset, hey we die we restart, no hard feelings even if it's bugged hard at times. Have a good day :)