Two points from one rally?

My friend told, that in a recent first round match in Arctic open between Ng and Oldorff, umpire mistakenly gave two points from one rally. First, I thought this cannot be possible, but the BWF video shows that happened.

In the second set, Ng was leading 13-8 and punched shuttle close to line. It was called in and points were set to 14-8. Oldorf challenged (point was not returned), and the challenge was unsuccesful. The umpire gave then a second point to Ng and 15-8 was on the screen.