Had a similar issue while double-carrying. Had Mp5 in my hands and found two cans of food in one house.
- opened first can with stone knife (drag/drop knife onto can, select option from context menu);
- initiated Eat All from context menu, without dropping the mp5 first. gun was put down and character began to eat.
- while eating animation, i opened second can (same methode as in point 1).
- when eating animation has ended i tried to initiate Eat All on second can.
- there was no reaction for several seconds. Then, i got "cannot interact/pick up item" error and eating animation on second can began.
- by that time, mp5 was gone. it did not come back on reload, it didn't appear anywhere around the building i was in.