He was clearly fouled before the clock hit zero/the backboard light came on. What happened was a foul was called/the whistle blew with tenths of a second left on the clock. As soon as that foul is called the clock should stop but you still would then have the continuation of the play resulting in the made basket +1. It is why after review they put .3 on the clock and the Suns had to inbound the ball.
