I’ve been reading this and related threads on several community forums, because I have also occasionally seen missing images as displayed by Pix4Dcapture on an iPad. Since I recently completed a sequence of long, straight flights of two “rows” each, side by side, I noticed some things that suggest temporary failure of the radio comm link is a potential cause of missing images. A little background: Pix4Dcapture on iPad 9.7 Pro (GO 4 was completely terminated while Pix4Dcapture was open); DJI Inspire 2 with stock remote controller; onboard KlauPPK GNSS receiver for PPK; images MicroSD card marked ‘SanDisk Ultra PLUS 64GB XC1 V10’; Distance from remote to drone at far end of flight paths before turnaround to Home: 4,000 - 4,800 US feet over drained tide flats; Rural area with no tall buildings; Drone approached a steeply sloping hillside just prior to turnaround to Home on all flights; UAV Forcast app suggesting less-than-optimal GNSS satellite constellation and worsening Kp Index; Wind minimal at 5-6 knots; 75/75 overlap.
That day, did I constantly maintain the angle and orientation of the two antennas as instructed in the “Optimal Transmission Range” section of the DJI Manual? Probably not consistently. These were 12-14 minute flights and I could have wavered in how I held the remote up/down or off-axis to the drone as it flew toward the far turnaround waypoints. On one flight there were no problems near the turnaround. On three others there were several missing images and odd positions near the turnaround. As the drone approached the far-off hillside, it was probably losing sat locks because of proximity to the hill.
Atypically, on one flight there were 5-7 images missing on the outbound path toward the turnaround (I did not see that many images missing in a row on any of the other 18 flights). I was not aware of the missing images until returning to my office that day.
For the next day’s flights, I tried to avoid any situation where I was as far away from the drone like on the previous day, and I paid more attention to “aiming” the remote’s antennas to manually track to the position of the drone. Afterward, I did not see problems at the turnaround points in those flights. I did occasionally see a missing image, but that was rare and not a big issue for this project. Perhaps those few missing images were caused by a brief comm link dropout because I was near a few houses, some of which had metal roofs. I used the same MicroSD card for image recording on both days.
All that said, the missing or shifted images on both days might be attributed to another reason(s) as suggested on this and other threads.