I was flying today with Go 4 v4.1.15 on an Android phone and the icon for my RC signal strength disappeared when I lost one bar. The RC screen icon was visible and functioning but the app icon was missing and did not reappear when I flew back to the full strength level. I had to land and reboot the app to get the RC icon back, but it disappeared in the same manner during each subsequent flight. I tried rebooting and reinstalling the app but it still lost the RC icon when the first bar dropped. All other functions and icons were normal. I could still fly with the RC meter but this is a first for me.