I was playing with my friend and I was trying to give him a blood test kit to see if we were compatible with transfusions. When I found one I dropped it to let him test his blood and he couldn't see it on the floor but I could and after I dropped it I couldn't pick it back up. The same thing happened when trying to pick up loot off another player. The items I was trying to pick up from another survivor wasn't registering until I left the server and joined back.