Pinephone: Severe artifacts in apps using latest GTK4

Describe your issue

What's the expected behaviour?

Apps using upcoming GTK 4 versions should appear correctly.

What's the current behaviour?

Apps using nightly GTK 4 have severe visual artifacts when using the default NGL renderer. Passing GSK_RENDERER=gl suppresses the issue.

How to reproduce your issue?

• Use Flatpak to install a GTK 4 app, such as Solanum: flatpak install flathub org.gnome.Solanum
• Install the nightly runtime: flatpak remote-add gnome-nightly https://nightly.gnome.org/repo/ then flatpak install gnome-nightly org.gnome.Platform//master
• Run the app using the nightly platform: flatpak run --runtime=org.gnome.Platform//master org.gnome.Solanum
• Severe artifacts appear in the window (see screenshot)

What device are you using?

edge (master branch)

On what environment did you encounter the issue?

Phosh

How did you get postmarketOS image?

from https://images.postmarketos.org

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

Not sure. All the apk packages are up to date.

Additional information

Corresponding GTK issue: https://gitlab.gnome.org/GNOME/gtk/-/issues/3894

Screenshot