Primary external display timing out

I've noticed a particular issue which I can't pinpoint the cause for. On my laptop I have a Lenovo Legion with a Radeon APU + nVidia GPU. Two external monitors are connected to a USB-C dock via DP and are working normally, whereas the internal display is mostly closed and am working on external monitors. Pretty regularly the unused monitor goes blank for a second or two before coming back again, which is a bit distracting, present when I do something off screen mostly and ignore the monitor for a while. What's curious is that issue appears too for my other desktop machine which has a single monitor plugged in, but on it timeout happens still without nay pattern. All power saving for displays is turned off and the monitors have been set up as in the pictures below.