I began a new habit today. I began mousing over cans of pop and selecting DRINK POP from the action menu. I used to take them into inventory and then drink them. I then had weird issues with my inventory.
I had empty, unusable inventory slots. Also the clothing or pack that contained the empty slots was flickering a bit.
I switched servers. Upon relogging, I noticed that my inventory was full of empty pop cans. The cans that I drank became invisible empties in my inventory. They only reappeared after restarting a new server/game.
I do not know if that helped flickering inventory, as I did not put the two together until after reading some reports on here. I suspect this may have some association with the FPS drop/crash/memory leak situation.