Ok never mind. It just happened again after receiving WhatsApp notification with sound then it started to repeat itself screen off, screen on and notification sound so on so forth.
So navigation buttons didn't work.
Device: Mi 9 (cepheus)
Rom: 20.12.28 (dirty flashed over previous)
Problem: When I start watching a YouTube video and previously in about 10-15 minutes of watching my screen starts to act weirdly. Screen turns off by itself and turns back on continuously. Touch becomes very laggy and can't stop...