I've managed to recreate it twice in the past half hour. Seems to occur more often from a warm PC. By that I mean PC running for a while. Shut down and restart without switching off at the mains plug. Power is still going to the monitor.
Tried this and got it to recreate the error twice.
Only way to clear it seems to be shutdown the PC. Switch off at mains outlet. Count to 10 so current clears and reboot. Then It didn't recreate the error. Obviously it does occur from cold now and again though.
Love the monitor and my only worry is that is this damaging the monitor or is it going to get worse?
I've been able to reproduce the issue even without any video cable plugged into the monitor, i.e. by just turning it on, but as you mentioned it's not something that occurs consistently.
Although not related to the power-up glitch, and I'm probably opening a whole new can of worms now, be aware that this monitor is also susceptible to image retention / burn-in. While running the EIZO uniformity test at 25% gray tone, I recently discovered that my unit has developed image retention of different elements that are constantly displayed such as the Windows taskbar, some desktop icons and the browser window. I have followed some recommendations to fix this without any success (unplug the monitor, run YouTube patterns, etc.)
So, about the possibility of damaging the monitor, I think it could happen if you inadvertently let the display to remain in the 'glitched' state long enough to develop image retention/burn-in of the vertical lines. Mine exhibited temporary image retention of said lines shortly after one of those 'seizures' but fortunately cleared up right after unplugging/plugging back the monitor (the other elements mentioned above, like the taskbar, icons, browser etc. are still there), if more time had passed, however (e.g. if the PC had woken up automatically due to a pending system update) who knows what might have happened.
I was somewhat willing to live with this power-up glitch but after discovering that image retention is also an issue, I have decided to start the return process and look for alternatives.
I also managed to get it to do it without it plugged in. Looks like it might be time to contact Samsung UK Support and see what the score is?
If you choose to go with the support route, they will probably dispatch a technician to your home or ask you to send the unit to a repair centre to have it inspected and then attempt to repair it or authorize a replacement. Personally, I would find this an unacceptable solution given how widespread this issue appears to be (we are now at 14 confirmations in the last three months and counting, including two replacement units). In my opinion, an investigation and product recall is in order.
I have this situation as well with my monitor. I bought this in mid January. So far, only a total reboot will work. Can't tell you what the production date is since its in a hard place to get to where the montior sits. I may end up returning this unit since I am nearing my 30day return.