I tried to fly today after receiving my repaired  RC.  It's been gone for a month having a broken antenna repaired by DJI.  I updated RC and Mavic firmware, linked RC to bird and was all set to go.... or so I thought.  Every time I fired up the system up, the RC would connect fine and give me the "Ready" message but after about 2 seconds, the video would go away.  A check of the aircraft status showed "gimbal disconnected" and Battery Temp: N/A.  In WiFi mode all functions and indications were normal.  Every time I tried RC mode, I'd get the same results.  I tried refreshing RC & Mavic firmware, relinking RC, went back and forth between WiFi & RC modes multiple times.  Basically I was getting increasingly frustrated as I tried and retried everything I could think of.  I was about ready to contact DJI when it occured to me that I was using a different firewire cable then I had been using before sending my RC off for repair.  I connected the original cable and sure enough, that fixed my problem.  Makes me wonder how many of the "mystery malfunctions" pilots report could have been attributed cheap or faulty cables.

Lesson learned:  Use a good quality USB cable and consider it another key component of the system along with the controller, IOS/Android device and Mavic.

I agree, an awful lot of what I read here sure sounds like flaky cabling.

Thank you for sharing your experience here.
Hope you enjoy your flight with DJI product.