Please reset the Monitor and check if the issue remains the same.

Please try the monitor on another PC or please try another monitor on this PC in order to isolate the issue. In this case, I suggest you to follow the steps given below to check if the issue is resolved. I apologize for the inconvenience caused and I will be more than happy to help you. I understand that when the monitor goes to sleep mode it flashes colored screens and does not go off. *Thank you for contacting ASUS Customer Service.

The end of my second chat resulted in this: So I fired up the next chat session and confirmed that the way to reset is on the settings menu as one would think. **I have now had two chat sessions, the result of the first was bogus reset instructions that did not pertain to this model. Shipping wasn't cheap and I am officially done with Asus products unless they can resolve this in a timely manner, but at this point my monitor has had this issue for well over a month now. The monitor got in on a Friday, with the RMA going complete within hours of delivery to their service center. Zero feedback from support on what was actually done. Mine also was sent in, just got it back today and it is in the EXACT same state it was before.

Asus rog swift pg279q microcenter