Watched my buddy Dave nearly return a brand new monitor last month. He spent days complaining about random black flashes during work. Turned out his DisplayPort cable wasn't fully clicked in at the back. Gave it a firm push until he heard the snap, problem completely gone. He felt like a genius for fixing it but also silly for almost driving to the store.
Honestly seems like a basic thing to check first. People make it sound like a huge discovery when it's just a loose plug. Not exactly rocket science to fix.