Brief flash of desktop contents when laptop wakes up to lock screen.

[DiesHorribly]

(Hopefully this is the correct sub-forum to post in)

Any time I lock the desktop and walk away long enough for my laptop to go to sleep, I see a brief flash of my desktop and the contents of anything open as my computer is waking up. I have an external monitor attached to the laptop, so that could be a factor in why this is happening. It isn't necessarily an issue for me but thought I should share as this must be unintended behavior. To clarify: I already have a running session, the computer is not booting. It is just waking up after I lock it to walk away for a bit.

I'm not sure what information is relevant to include, please let me know what I can add to this post.

I use a HP ProBook 455 G10

KDE Plasma Version: 5.24.7
KDE Frameworks Version 5.92.0
Qt Version 5.15.3
Kernel Version: 6.5.0-26-generic 64-bit
Graphics Platform: X11

[Snowhog]

I see a brief flash of my desktop and the contents of anything open as my computer is waking up. I have an external monitor attached to the laptop,

This brief flash of the Desktop. Do you see it on the laptop screen, the external monitor, or both?

Welcome to KFN!

[Schwarzer Kater]

Welcome and thanks for sharing.

This sounds like a small delay between showing your desktop and showing the desktop "covered" by the lock screen?
Does this also happen when the external monitor is not attached?

If it is a small bug in Plasma it will quite certainly not be fixed anymore in Kubuntu 22.04 LTS as Plasma 5.24.x is in a kind of "security bug fixes only - if at all"-mode (if I understood it correctly).
You could try if this also occurs with a newer Frameworks (or newer Frameworks and Plasma) version, meaning: with the Kubuntu Backports (and Backports Extra) PPA(s) enabled (but have prepared some way to revert your system to a previous state in case something goes wrong) - see e.g.
KDE Plasma 5.27.10 available in Kubuntu Backports Extra
and
Overview: Kubuntu, its parent and some of its siblings

Personally I would try the Kubuntu Backports PPA only first, and if this would not help (or if I wanted to have Plasma 5.27.x) additionally the Kubuntu Backports Extra PPA.

[DiesHorribly]

This brief flash of the Desktop. Do you see it on the laptop screen, the external monitor, or both?

Welcome to KFN!

It only occurs with the external monitor connected. I tested it a few times to be sure.

Welcome and thanks for sharing.

This sounds like a small delay between showing your desktop and showing the desktop "covered" by the lock screen?
Does this also happen when the external monitor is not attached?

If it is a small bug in Plasma it will quite certainly not be fixed anymore in Kubuntu 22.04 LTS as Plasma 5.24.x is in a kind of "security bug fixes only - if at all"-mode (if I understood it correctly).
You could try if this also occurs with a newer Frameworks (or newer Frameworks and Plasma) version, meaning: with the Kubuntu Backports (and Backports Extra) PPA(s) enabled (but have prepared some way to revert your system to a previous state in case something goes wrong) - see e.g.
KDE Plasma 5.27.10 available in Kubuntu Backports Extra
and
Overview: Kubuntu, its parent and some of its siblings

Personally I would try the Kubuntu Backports PPA only first, and if this would not help (or if I wanted to have Plasma 5.27.x) additionally the Kubuntu Backports Extra PPA.

Thanks for the advice, I'll do that.

[Schwarzer Kater]

You are welcome.
But I have not suggested the most obvious: did you already try if this also occurs with a new user account?