Hi , I was flying in a park today and decided to go over a gorge to do some aerial shots of the road bridge. I flew up over the trees and headed to the gorge, when the mavic got there (around 1500ft away) the maps on my iPhone disappeared and the video feed cut out. On the controller I didn't notice a "loss of signal" or anything , I waited for 10-15 seconds and it still wasn't relaying video so I initiated a return to home which it did. When I got the Mavic back home I viewed the onboard footage from the memory card and as soon as the mavic cut out from the phone the video start to jitter/ freeze and then goes out of focus. The mavic then returns home as instructed and the video remains out of focus until it is about 200 ft from me where it seems to reset. On my flight log the mavic just disappears and jumps back near me after being frozen still for a long time. Any ideas at all pls as Mavic Support don't have any ideas?