I looked at the game log and it looks like the statistician indeed counted it as a sack. I looked up the rules for a sack on a passer and it looks like it is up to the statistician's discretion whether or not to award a sack or a tackle for a loss. If the passer shows intent to throw a forward pass and is tackled behind the line of scrimmage it will be counted as a sack. The thing about that play though if I remember correctly Hunter pulled the ball down and tried to run the ball at the last second. Looks like you just got boned by the statistician, bad luck.
If you are referring to the play where they were trying to run a half back throw option they may have counted it as a sack since he pulled the ball up into a throwing motion. Not sure though, I barely remember the play.