Bug or not?

Currently having a lot of fun trying demon hunter in wild. With 1 mana hero power and occasional cost reduction from skull of guldan suddenly some cards with inspire became much more interesting.

Anyway, with Baku you get an upgraded hero power, which gives you 2 attack instead of 1.

But, if after mulligan at the start of the game your leftmost card is eye beam, it gets outcasted, which means it costs 0. Suddenly, your Baku does not activate and you get a normal hero power! 
Do you guys think this is how it should be?

This is definetly not how it should be. Baku has a deck BUILDING restriction.

Try posting this at reddit aswell, I know some game devs check there regularly an maybe it will be fixed.

You are not alone, I've been experiencing that bug as well. (Lost a game because of it, lol)

I think I lost my first game when I hit this bug as well. Turn 1 I tried killing their 2 health minion with my hero power, and was very confused when the minion only took one damage.

Well, I guess today’s nerf to eye beam fixes the issue: