How do I turn off the notification sound when opening my laptop lid?

When I open my laptop lid, I get a notification sound. This just started recently and I can’t figure out how to turn it off. I’m using KDE Plasma.

Do you have a notification in the tray area? Without knowing what produces the notification sound it is not possible to disable it. You could disable all system sounds but that’s not ideal.

Nothing in the notification tray. Oddly, I just opened the lid again and didn’t hear anything. I wonder if it was another program that was causing it but I’m not sure which. If I find out any more details, I’ll report back.

It seems to only do it if my computer hasn’t been used in a while, maybe after it’s been in hibernation. It sounds very similar to the noise made when emptying the trash.