xrandr scaling not restored after screen lock/display sleep

[emanruse]

Qubes OS release

4.2.2

Brief summary

After remaining for some time in locked screen mode, the original down scaling introduced by xrandr is not restored.

Steps to reproduce

Not sure if this is relevant, just extra info: On this system there are 2 displays - one 4K (primary, DisplayPort) and one 2K (secondary, HDMI). To have a matching scale, I set this when using either (A) both screens (side-by-side) or (B) only the 2K one:

xrandr \
    --output DP-2 \
    --scale 2x2 \
    --set "Broadcast RGB" "Limited 16:235"

1. While in (B) mode (only 2K screen, scaled as explained), lock the screen

2. Wait a few seconds or a minute

3. Move the mouse

Expected = Actual: scaling is fine

4. Wait more (e.g. 15+ minutes) - this seems to be the key to reproducing the issue. I have not measured the exact time, it seems to vary.

Expected behavior

The scaling should be preserved as set by xrandr.

Actual behavior

The specified scaling is not preserved. Everything displays as 1x1 (i.e. twice bigger), instead of 2x2 scaled.