Recently when I turn on Spark, RC and DJI Go 4app, there are indications missing in phone'e screen such as no. of satellites and battery level.
Usually when I turn off RC or Spark or both for one ot two times and then turn them on again, the indications  re-appear and I have a normal flight.
Today I encountered the same problem but after turning off and on everything for many times I did not get the indications back.
Anyway, I flew the AC for some time with no particular problem.
However, is very annoying  (not to say dangerous) trying  to fly without the necessary indications on the screen.
The problem does not appear in every flight but I think that the frequency increases.

What is going on?

These take a few minutes to appear usually,  especially the battery indicator.