I have an update of DJI Fly app in early July and found that there are two red lines, one in front of and one at the back of the "trangular" drone indicator. After several tests, I found that when I put something in front of my drone's front left obstacle sensor, the left side of the red line disppears. Same happens to the right sensor. As I can't find any discussion on this feature on web, I wonder if it is a new feature of the new DJI Fly app or something wrong with my drone.

Hi Thomas, could you please provide us some screenshots or a video to check the said issue? And please also tell us the model of your drone and the app version.