While flying yesterday I noticed my EV meter was stuck in -1.3 and wouldnt change. I was using a ND32 filter in a very bright day. The histogram was not blown either in the highlights nor the shadows. Shutter speed of 1/60 and I changed it to see if it would move, but nothing happened even efter obviously over exposing the image. It was stuck both on the app and Mavic RC

Everything up to date, iPhone 6s Plus

same here...EV reading is stuck most of the times no matter if i shoot the sun or shadows. I also use ND16 all the time.