I am not sure if that is intended or not.
I "tank" bear, while using blocks and occasionally hitting it. I noticed that when initiative reaches 2 it will sometimes attack twice (my usual block goes away and my "initiative" block goes away too). It caused me issues few times, since my "initiative" block also blocks green, so basically bear will break it and will onehit KO me into dust with instant second hit.
At least it looks like double attack. Sometimes it goes with longer pause in-between, sometimes you just get "unlucky" KOd or, if shield was last - survive with both blocks down.
It can be worked around when known, of course, but it feels like it might be unintended behavior (since we all have CDs on all abilities).