Hex Blast not removing all curses

The little video explaining how Hexblast works show and explains that it will remove all curses on target cause a blast for each one removed. Using Enfeeble and Despair with blasphemy, and when I use Hexblast it only removes one of the curses.

I'm also encountering this.

Edit: I also tested this self-casting two curses and only one is detonated by hex blast per cast.

BUMP
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I made my entire build around speccing into a blood mage critical hex blast curse stacking and am now bricked because of the bugged interaction only detonating one curse. The video for the ability says "If a monster has multiple curses all of them will be detonated."