Created attachment 143116 [details]
Carla patchbay screenshots, from fresh reboot to multiple applet open

SUMMARY
On my machine, I have Pipewire installed as a JACK (and PulseAudio?) replacement. After creating a coupled stream virtual device according to https://gitlab.freedesktop.org/pipewire/pipewire/-/wikis/Virtual-Devices#coupled-streams, plasma-pa doesn't disconnect to the virtual device after the applet closes, even though it disconnects from the "built-in" audio devices (observed in Carla patchbay). Also, probably because of that issue, plasma-pa creates new connection ports each time the applet opens, with each new ports connected to the virtual device not disconnecting and further bloating the patchbay.

STEPS TO REPRODUCE
1. Install Pipewire and Carla.
2. Create a virtual device, following https://gitlab.freedesktop.org/pipewire/pipewire/-/wikis/Virtual-Devices#coupled-streams.
3. Open Carla and go to the patchbay.
4. Open the plasma-pa applet several times.

OBSERVED RESULT
The Plasma PA 'device' in the Carla patchbay persists, with each call to the applet creating more ports for the virtual device which doesn't close.

EXPECTED RESULT
The Plasma PA 'device' in the Carla patchbay should properly disappear each time the applet closes.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
I have `pipewire-jack-dropin` installed. But it probably shouldn't matter.
Pipewire version: Compiled with libpipewire 0.3.39; Linked with libpipewire 0.3.39
Using Carla version 2.4.1
Python version: 3.9.7
Qt version:     5.15.2
PyQt version:   5.15.6x