Usually Boomer will beep and consider the ball “good”. Boomer hides a bit of the court from the camera’s view so if it sees the ball disappear behind Boomer, it gives you the benefit of the doubt and calls it “in”. Sometimes the ball may bounce back into the court which can confuse Boomer into calling this ball rather than the next ball. Aim for the corners and this won’t happen. Also don’t put ball hoppers or anything near Boomer that could bounce a ball back into the court for the same reason.