@ hapticdata - This does not sound like the same issue that I had. Mine did not have anything to do with how long the monitor had been on. It did have to do with activity, though, such as displaying something new on the screen. The monitor would black out for always exactly the same amount of time, maybe one second, and then it would come back. It didn't do it more or less after it was warmed up. Mine was a firmware problem. Yours sounds more like an intermittent connector problem, or bad solder joint around an electronic component that warms up with use, to be honest. I understand why you are upset. I was very upset with mine, and was quite vocal with Apple during multiple calls to their tech support, multiple trips to the Apple Store Genius Bar. and here on this forum. The firmware flash cured the problem completely for me, and I am back to loving the display, and I appreciate Apple for sticking to it and fixing firmware on a monitor they were no longer selling. In the mean time, I bought a different well known brand, also LED backlit, and that was quite a mistake. No where near the quality. If your flickering is like mine was, always the same time black, it might be that your reflash didn't take. If it has longer and shorter black times, look at connections.
For what it is worth.
Bill