Not to be pedantic, but are you sure this is an (illegal) forward pass? As described, very technically he pitched (threw) it forward, from 5 yards deep to the official behind the GL pylon (assuming when he let it bounce past him, it was out the side of the EZ, and not at the 1 or 2)?
What I'm getting at (thinking out loud here), let's assume that A runs a play from the one yard line. Snapped to the QB, who is 5 yards deep in the EZ, who then throws the ball to A22, who is 1) 2 yards in the EZ, or 2) 6 yards in the EZ. In both cases, A22 throws a long pass to A87 who catches it at the A35. 2 is definitely legal; but is scenario 1 a legal or illegal forward pass?
I've always assumed that anything behind the GL was treated as still behind the GL. That may not necessarily be true, the more I think about it.