Trying to place a mordanted scarf into a cask with dye gives the text "There's no room in there" and doesn't let you place the item in. In particular, the item is a great quality mordanted scarf and the barrel is half-full of phoenix dye. 

1. Have an opened cask with dye in it

2. Try to click and drag a mordanted tailored item into the cask inventory box

3. Error "There's no room in there" text