So when my computer goes into what I assume is sleep mode, the screen and keyboard flicker showing whats on the screen. This is a recent problem and I can't think of anything that I changed that would have done this
I just had the same problem. Have five 27" monitors and, when in sleep mode, would flash quickly but not all at the same time. Custom build PC. Video using EVGA GeForce GTX 1060. Going out of sleep all was normal but seemed to have high CPU use - Crucial Ballistix Sport LT 32 GB. The task manager shows an odd server host tied to the audio card, as I recall - weird since nothing active.
The blinking started after outlook notified me I had an update to do. I did update but had not done windows latest updates for maybe a month since that long since rebooted.
The blinking was cured by doing the Windows update. However, while my shortcuts on various monitors were in the right places, I have lots of "fences" that had mostly moved to my main monitor.
Moved back to where belonged, and no more flashing monitors in sleep mode!