Can't make 5 Dose Ant's Potion - Green Server

[fizzlefest]

Playing on Green Server. I wanted to make myself a 5 dose Ant's Potion since Shrink isn't in the game yet. I have 5 single doses in my Bearskin Potion Bag, yet when I hit the combine button, i'm told "You cannot combine these items in this container type."

Don't know if this is a bug or not possible to do yet according to the timeline (I've made 5 dose SoW potions on Green). Any thoughts? Thanks!