This is a two referee play as the lead moves with a purpose to get strong side. Black #7 establishes his left foot as his pivot and lifts that foot before the ball is released. This play is a NCI (no call incorrect). To have a higher percentage in getting this play correct, the trail official needs to take a step down to referee the play with an open look.
As we referee the defense we still need to ensure that the offense is legal. In this play watch as the trail official recognizes that Green #42 establishes his right foot as his pivot. The official correctly calls a travel as his right foot moves before the ball is released.