I just put together a new desktop and I'm using an AMD Radeon RX 590 Series card.
In Settings-> Power I set my displays to go blank after a certain period of time. For example, lets say I set my monitors to go blank after 5 minutes. Indeed, after 5 minutes of inactivity, my displays will go blank/dark. However, after a few seconds, my displays will 'wake up' and the lock screen will be visible. A few seconds pass and the displays will begin to go blank/dark again but will ultimately 'wake up' to the lock screen after a few more seconds. This process repeats over and over with no end.
This happened with both 18.04 and 19.10. I'm using whatever drivers are installed with a normal Ubuntu install...nothing proprietary.
Any idea what might be wrong or how I could resolve?
In the past I've seen this weird behavior before with a failing mouse or keyboard but even when i remove the USB dongle for these devices, my monitors still 'wake up' after going blank.