Backcourt ruling?

[Mo-Money]

I cannot find the ruling in the book or a scenario of any similar plays that would help me clarifies whether this is backcourt or not.

A1 is dribbling in his/her frontcourt. A1 then passes the ball which gets deflected by B1 into the air and crosses the midcourt line but before the ball touches the floor A1 runs to the backcourt and catches the ball before it hits the floor. Is this backcourt or not?

The trail official gives the new tip mechanic to let everyone know that the ball is fair game to either player.

I say its backcourt but my partner said no because it was tipped by the defensive player.
If this is a backcourt violation can you please give me a reference that supports the ruling.