Every app restarted (not a complete phone restart)

[prashanth]

I was watching youtube and suddenly my phone stopped,i locked it and tried to unlock every app including my live wallpaper restarted and reloaded like they were forced out of ram.Is this common or something that i should be concerned. @Anders_ASUS
Headsup:
I have had instances earlier where my phone stopped working entirely(screen blank to be exact) not able to start any apps....i happend twice but it was long time ago

[Anders_ASUS]

Try safe mode (boot with volume down + power) and install another launcher. Restart and try the other launcher.
But even if it does work, I'm pretty sure the best way to fix your issue is by resetting your device

[prashanth]

It happened again and it was again with the same app(call of duty mobile) i was switching back and forth with some other app and my phone got locked again.....this it showed a NOTIFICATION saying system being optimised....
Whats that supposed to mean???? @Anders_ASUS