Before yesterday I was in a flight when the DJI Go app jumped out to the screen where You can choose the device what You will use. I was not able to do anything and after a few seconds the app jumped into the scrren what You can see when You use the app for Osmo device. I saw the picture of the camera in live and I was able to control my Phantom 3 SE. I got a message - still in flight - about neccesary firmware update and that was the point when I made a landing and turned off everything. As I was in recording I've checked the video but it was OK I was not able to see the point when the app made the change.
After the restart everything was OK and during the next flight there was no issue - expect the common "low signal" messages what is an other topic.

Did anybody has the same issue before? It was really scary as I was not sure I will be able to land properly...

That's a new one for sure.  Anything can happen these days.

in 4 months I have my phantom 3 SE , it has happened to me about 3 times, the solution is to restart the application, in my case