Guild Wars 2

Recently I have encountered several issues of unstackable stackables. There seem to exist different versions of same items – different either because of when or how they were acquired. So, keeping these items ready for different characters means reserving double the necessary amount of bank space.
Among these items are Crafting Boosters, Gathering Boosters, Rejuvenation Boosters, Tomes of Knowledge and Gifts of Exploration.
Since bank space is a finite resource and it is quite annoying to see it wasted so recklessly it would be very nice if such double-stacks could be avoided. If the creation of a new version of a given item is necessary, please provide a method to transform older stacks to the new version to avoid confusion and further waste of bank space.

It’s a bug. Put them in your inventory, change maps, and then restack them.