Dead Ball Foul

[hoopsjw]

A1 drives to the hoop and makes a layup, while losing his balance. B1 starts to take the ball out of bounds after the made basket. As he is beginning to throw the ball back in, A1 starts to turn around from out of bounds to run down court and flattens B1, as A1 was not paying attention. My partner called a personal foul on this but it does not seem to follow the definition in 4-19-1 and 4-19-1 Note. Should this have been a no call unless it was intentional or flagrant or was this done properly? Thanks.