Official comment
The red is not the end of the world if it is limited. It is there as a heads up that you are certainly getting more blur that you want though.
It sounds like you have a large dark area (maybe a more shaded north facing hillside) that is needing much longer exposure times to capture the image.
There is no way for the user to manually adjust the speed of the flight while the aircraft is in the air since the entire flight is programmed before takeoff. The Light Conditions slowing feature makes a quick adjustment before the aircraft gets too far out of range after making some light measurements on the way out to the green dot.
You could manually adjust the ISO on the camera if you are using the Manual exposure mode. You could also manually adjust the exposure compensation when you see this happen to shorten up the exposure times. This can be done on the remote's right click wheel.
We always recommend collecting your data at the brightest time of the day with the exception of 1 hour before or after solar noon to avoid travelling sunspots in your image sets.
Simulated flights will almost always show the ground smear number in the red zone since the camera is probably just pointed down at the table or something. You can check to see its function by taking the flashlight on your phone and sliding it up under the camera to change the exposure time to the much shorter end. That will make the blur get back in the desired range for simulation.
