No idea what triggers this (the defense?) but there four instances in this game of the QB dropping back and standing perfectly still until he was sacked:
http://mfn1.myfootballnow.com/watch/1825#325957" target="_blank"> http://mfn1.myfootballnow.com/watch/1825#325957

http://mfn1.myfootballnow.com/watch/1825#325979

The second link is immediately followed by another instance