I am having the same problem.
All of a sudden after not using the drone for 1 month, I have a very bad feed. It's not the usual glitches which have plagued my drone experience, it's the drone constantly disconnecting, the screen going black, the drone reconnecting/disconnecting every other second and all of the display options (including record button) flashing on and off rendering it utterly impossible to see anything or press anything.
I have no problem using the goggles via HDMI output and I have tried different USB cables/devices (ipad/iphone) which haven't helped.
I spoke to a support helpline who suggest it may have something to do with the latest iOS - but if it's happening to Gump with the Samsung s7 then that's ruled out.
Would appreciate any further ideas...