error creating screencast "Failed to connect PipeWire context" when starting plasmashell in Debian/KDE

Why do I get this in the console when restarting plasmashell with killall plasmashell and kstart5 plasmashell in Debian11/KDE with Wayland and how to solve the problem? Of PipeWire I currently only have libpipewire-0.3-0 installed, I searched for screencast in Apper but don't have anything of that installed. I'm using PulseAudio and I think I also got this error when I ran something else than plasmashell but it's probably the same cause. I'm not screenrecording but have some apps that can do so. I tried uninstalling xdg-desktop-portal and this reduced these errors but the error still shows, it went from 8 times the above error to only one:

error creating screencast "Failed to connect PipeWire context"
trying to show an empty dialog
DataControlOffer: timeout reading from pipe
DataControlOffer: timeout reading from pipe
DataControlOffer: timeout reading from pipe
DataControlOffer: timeout reading from pipe

**Edit**: it's two errors now and unlike before these only occur after waiting for approximately 20 second after starting plasmashell (the other errors are because of kdeconnect trying to start without being configured to so which I blocked and asked about separately):

...
error activating kdeconnectd: QDBusError("org.freedesktop.DBus.Error.Spawn.ExecFailed", "Failed to execute program org.kde.kdeconnect: Permission denied")
kdeconnect.interfaces: dbus interface not valid
kdeconnect.interfaces: dbus interface not valid
error creating screencast "Failed to connect PipeWire context"
error creating screencast "Failed to connect PipeWire context"
libpng warning: iCCP: known incorrect sRGB profile

**Edit 2**: this error does not occur on another machine with nearly the same setup. Plasmashell is version 5.20.5 in Debian11. The same error occurs again when waiting for a while. How can I find out the source or traceback of this error message (may be a separate question)? I'd like to find out what software causes it, it's probably something that plasmashell launches. **Edit 3**: after upgrading to **Debian12** and resuming from sleep these lines show in journalctl shortly after resuming. Why and what should I do:

systemd: NetworkManager-dispatcher.service: Deactivated successfully.
kwin_wayland_wrapper: kwin_screencast: Failed to connect PipeWire context
kwin_wayland_wrapper: kwin_screencast: Failed to connect PipeWire context
plasmashell: error creating screencast "Failed to connect PipeWire context"
...

Is there some problem with kwin_wayland or a pipewire package missing? It seems like many people get these messages so some further information would be useful.