I cannot release empowered Evoker spells with Bartender on the DF Beta. It does not even begin casting if I hold down the button, instead it just sits as if I am not casting the spell at all. When I release the button, the Empowered spell begins casting, but I cannot release the empower level. I can only cancel it or let it fully empower (and hold for the extra time at the end).

Turning off Bartender and using the default Drangonflight action bars fixes this.

This is a Blizzard issue on the beta currently, but hopefully getting fixed in this weeks update.

This is now resolved in the beta.