This was never a problem for me before two weeks ago, but now I am encountering an issue wherein force feeding someone causes the item I fed them with to completely disappear. This happened to both of my canteens, much to my chagrin, and a brand new tin of tuna. The canteens didn't just empty down to 0%, they completely disappeared, as if the act of force drinking my friend caused the canteens to melt in the player's hands.
This also happened with the tuna. It didn't drop to zero, it just vanished.