It happened once, several weeks ago, when I tried the Follow me mode. The craft seemed to behave in a weird way, shaking on right and left side. The tablet (a Nexus 7 with latest Android version installed) start rebooting and it took a century to restart. That time the craft was at only 10 meters from me, so I could manage the situation.
Yesterday it happened again, but in a situation that I would define absolutely normal. Weather was good and the temperature was about 12°C.
GPS signal excellent, so I sent the craft along a valley with some ruins to take some video. After about 10-12 minutes of flight and a lot of video recording, I realized that the button "start/stop recording" apparently did not work... nor the throttle... nor the left stick... everything look frozen in the monitor.
The craft was a bit far (about 300 meters) and I could not easily understand if it was responding to the commands or if it was just the DJI Go App frozen (probably the second). Indeed, after several seconds the tablet turned off and start to reboot... Oh No !!!
Not having a clear view of the orientation of the craft (and not too far from trees) I suddenly replaced the Nexus 7 with my Sony Xperia Z2 (which also have the DJI Go App installed). The whole operation took about a minute. The Xperia Z2 connected to the craft and the DJI Go App asked me if I had permissions to fly over a Class D zone (But on the Nexus 7 it did not gave me any warning of such kind, and also this detail would worth opening a new thread).
Finally I managed to get the craft back with the support of the Xperia Z2, but is not pleasant to see the tablet freezing when the visual is not excellent. I hate the idea to bring two devices with the DJI Go App installed if one suddenly freeze.
I wish to understand the cause in order to prevent it from happening again.
My guess is that sending a continuous video stream trhough the USB cable to the tablet could somehow over-warmed the Nexus 7.
It is realistic ?  
In the other side, when I used my Xperia Z2 I was getting sometime get a message that keep saying something like "the connected charger is not enough to recharge the phone".
Could be therefore something linked the way the RC and the tablet communicate ? Any idea ? Anyone had similar experiences ?

Would you please help clarify your aircraft model? what is the firmware version for your aircraft and remote?
What is the mobile system of your android phone? APP is the latest, right?
Have you tried to delete it and then re-install? please disable all other background programs and cool it down before flight.
If still the same case, we will help you analyze the logs.

Hi Natalia,
Thank you for your reply.
The craft is a Phantom 4 with installed the latest firmware available from DJI.
Also the RC has the latest DJI firmware available.
The tablet is a a Nexus 7 with Android 6.0.1
The phone is a Sony Xperia Z2 with Android 6.0.1
Honestly I noticed that the DJI Go app wasn't the latest version. I updated it in both devices right now.
Regarding the background programs, the Nexus was purchased only for the Phantom 4, so it shouldn't have background programs running. Today I tried to stress the Nexus acquiring video from the P4 and I noticed that the body becomes quite warm, but not particularly hot.
Having installed the latest DJI Go App, hopefully the problem is fixed, but only using the P4 I can put the word "end" on the subject (until now it happened only 2 times on 85 flights).