varying image brightness when using MapPilot with DJI Phantom 3 Adv

I've recently flown a few flights using Map Pilot to capture images for processing into orthomosaics and I noticed that some images taken right before and after each other vary significantly in brightness.  There's be a darker image and then a 2-3 lighter images, then another darker image, etc. This is with an overlap of 75% so the photos are being capture with seconds of each other.

The images are taken over a forest at an altitude of about 400' so it's not like the content of the image is changing dramatically.

In looking through the csv Logs from the flight that I downloaded from my iPad, it appears that the LightSource value is switching back and forth between "unknown" and "Daylight" and that's what's causing the image brightness variations.

Does anyone know how to fix that so that it always uses Daylight or in some other way make the images more consistent?

Thanks,

Dave