When you press use, it should be the same as when you use a recovery item. It can only be used outside of battle. It should work the same as when you use a food item.
I played through all the new content using the file 8 save that came with the release, the bug appears to happen only with drinks, I can still give companions other items such as blood, food, etc, it is just a theory but I think it might have something to do with drinks not giving any bonuses. Haven't started a new game or used another built in save yet so I don't know if it is exclusive to file 8 or if it affects other non status items.