This is actually a bug which occurs when the player has used SoB while the opponent has a Sanctuary on the field, like so:
I have a SoB in hand, play it, wait for a turn to pass, then end my next turn without playing any cards:
As you can see, my opponent's turn has started and yet I still have a full hand. The deck I was facing consisted of 6 Sanctuaries and 12 Light Towers/Pends, so there was no way the opponent could have forced me to draw.
Attempting to replicate this bug has been successful each and every time.
