The problem being that the phone's display doesn't switch on when you wake up the device. At this time, Everything else will including the Digitizer and Capacitive buttons.
I have spoken with HTC service centers across Australia and NZ to come to the conclusion that this is a motherboard problem. The infamous flickering issue seems to be involved also, which ends up shorting out the video driver.
The issue isn't just limited to the screen not displaying anything either, there's also the possibility that the back light will cut out, and sometimes leading to corruption on the display.
This isn't just with some devices either, it seems like anyone that has had the screen flickering issue are at risk of this.
To give you an idea of how much it costs to fix this issue, I was quoted at $250 AUD for just the motherboard alone.
The best part is, HTC may also deny your warranty for unlocking your bootloader, as they have with me.
I'll be posting more information as it develops.
EDIT 29/07/12 :: I'm going to request a transcript of my last conversation with HTC but until then, they're denying that this is a problem and saying that it's the user's fault. How? We use our phones to much, or inappropriately.
It's becoming obvious that they're trying to avoid spending anymore money fixing these issues, and have decided just to move on and release a new One X model. (according to news sources.)
Also, Boobinator just posted a video of the One X's screen corrupting while it isn't stuck under the BSOD which you can see here and here
Just to recap.
When the initial issues were found with screen flickering and corruption on the display, we were told it was a software issue.
Many months later, I along with many of you are still experiencing it, even though it's not nearly as bad as it once was.
Now there are growing reports that One X's are starting to lose their displays, and the poly-carbonate weakening and bending the antenna pins. (You can find more information here)
This is something you should all be aware about when purchasing this phone.
Best of luck!