Cannot start Flathub apps on pmOS edge with systemD & Phosh [bwrap error]

Describe your issue

What's the expected behaviour?

Flatpak apps should start when clicking on their icon in the app overview.

What's the current behaviour?

• The app closes itself automatically after the loading screen. The loading seems to take longer than usual.
• in the Phosh app overview, the icon has a visible border.
• When staring through the console:

flatpak run info.febvre.Komikku

bwrap: Unexpected capabilities but not setuid, old file caps config?
error: ldconfig failed, exit status 256

The same is true for seemingly every Flatpak app, for instance org.gnome.World.Secrets or org.gnome.World.Citations.

How to reproduce your issue?

Flash pmOS edge, go to the software store and install an app from the Flathub source.

What device are you using?

google-sargo

On what postmarketOS version did you encounter the issue?

• edge (master branch)

• v24.12

• v24.06 (supported until 2025-01-23)

• I confirm that the issue still is present after running sudo apk upgrade -a

On what environment did you encounter the issue?

Environments

• GNOME Shell on Mobile
• Phosh
• Plasma Mobile
• Sxmo (Wayland/Sway) Please post the output of sxmo_version.sh
• Other: Please fill out

Which init system are you using?

• OpenRC
• systemd

How did you get postmarketOS image?

• from https://images.postmarketos.org
• I built it using pmbootstrap
• It was preinstalled on my device

What's the build date of the image? (in yyyy-mm-dd format)

2025-02-20

Additional information

Output of bwrap:

bwrap: Unexpected capabilities but not setuid, old file caps config?