OBS hang on adding JACK input source [flatpak]

Operating System Info

Other

Other OS

Debian Testing (bookworm)

OBS Studio Version

27.2.4

OBS Studio Version (Other)

No response

OBS Studio Log URL

N/A

OBS Studio Crash Log URL

N/A

Expected Behavior

I would expect the JACK input client to be added and become configurable.

Current Behavior

When clicking "OK" on the source creation, OBS just hangs. It never crashes and the logs before and after attempting to create the source, do not change. As such there are no logs to provide

Steps to Reproduce

1. Already have a system configured with JACK and pulseaudio
2. Install OBS using flatpak (doubt that the distribution matters)
3. Add a JACK input client
4. OBS should crash at this point

Anything else we should know?

I use the Flatpak version of OBS in order to take advantage of the Browser source, as the 27.2.4 version from the Debian repositories doesn't seem to have that source available.

Background on the desire for JACK. I have an external sound card and I make use of JACK to have more control over the input and output routing of the device. I was hoping I could take advantage of the JACK source for VLC (possibly other devices), as having VLC output direct to JACK, is not captured by pulseaudio.

JACK input capture works just fine with the Debian package, but don't have the browser source available.

Start by reproducing the hang when adding a JACK input client through the Flatpak build on Debian Testing with JACK and PulseAudio configured. Compare this behavior with the Debian package, where JACK input capture works, and inspect the source-creation path for the point at which OBS stops responding. Done means the JACK input client is added and configurable without hanging.