Update: My monitor is working perfectly as is. Zero issue. It seems my monitor never had any issue to begin with. The proximity I switched to High set the the screen to black screen after I believe 5-10 minutes if it doesn't sense anyone sitting 2 fe...

I think my issue is fixed now after changing my Proximity from High to OFF. I no longer getting black screen after playing a game past 10 minutes or sitting far from the monitor. My firmware is 105. Maybe try resetting your monitor settings to factor...

Is your Proximity setting turned off or off? if off its probably why it's not turning back on because the proximity if turned on it can sense motion in front of the monitor. I have it turn to high and when i move in front of it it will turn back on. 

I have the same issue like you with firmware 105. What is the max distance the promximity sensor sense a person in front of it? I think mines turn off the display (black screen) after 10 minutes or so and I have to move closer to the monitor or move ...