Originally Posted by zephiK
Seems like a app problem. Those tips usually appear when your phone enters immersive mode for the first time. After pressing okay once, it shouldn't appear again
If the screen is turned off and on again within 5 seconds while something is triggering immersive then it resets the flag saying that you pressed "OK". Panic feature in case someone gets confused because nav/status bars disappeared - most likely thing they're going to do is turn the screen off and on.
I've unintentionally triggered it myself many times, and others have too, hence the creation of some Xposed modules which disable it entirely.