Phone calling has weird behaviour on librem 5/phosh

Describe your issue

What's the expected behaviour?

Open calls app, type a number, start phone call, UI updates to show number is being phoned, call can be stopped.

What's the current behaviour?

Open calls app, type a number, start phone call, calls app closes, phone call actually occurs in the background somehow. No sound comes through (definitely related to #931 (closed)).

How to reproduce your issue?

Make a phone call on a librem 5 running phosh.

What device are you using?

Purism Librem 5 Evergreen

On what postmarketOS version did you encounter the issue?

• edge (master branch)
• stable (v20.05 branch)

On what environment did you encounter the issue?

Phone environments

• Phosh
• Plasma Mobile
• Sxmo

Other

• No environment
• GNOME
• KDE Plasma
• Kodi
• MATE
• Shelli
• Sway
• Weston
• Xfce4
• fbkeyboard
• i3wm

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)

a couple weeks ago

Additional information