I have noticed that the inventory becomes unresponsive after eating. Say I have three apples that I want to eat, I pull the first one to my hands, tab out of inventory to hold LMB to eat*, character eats the apple and when he's finished I tab to open inventory again, I pull apple #2 to my hands and it just bounces back to the bag so I have to drag it to hands again. Sometimes this happens twice before the item goes to the hands, only very rarely does it "stick" on the first attempt, usually when I've been distracted by something so it has been a few seconds before I drag the item in question.

*) That really should be doable without needing to tab out by the way! Let the action menu appear in the inventory when you hover the cursor over the apple/whatever and then automatically close inventory to show action animation when player picks an action.