Samsung Motion and gestures turning on by itself.

[Another Sone]

I have Samsung galaxy s6 (for 3 and a half years by now) and motion and gestures is turing on by itself. I can do nothing with my phone (because it says it's not recognizing my face), just wait for it tu turn off by itself.

It happened 3 times over past 2 months.
I never had motion and gestures ON, only for couple of seconds out of curiosity.

did anyone ever had similar problem? can that be fixed? is is a virus?
Thanks