If you give Banshees the "Blind and Silence" doctrin, and you're having Scorpions in your rooster, the button for their scream isn't changing. You see the bar in the button is filling up and it shows a 1, right after you build them. But after they used the scream, the button doesn't change. Actually there should be a 0 and the bar should fill slowly within 15 seconds.
Right now you have no indicator if the Banshees can use their scream right now or not.