Phone call and SMS issues with VoLTE on FP3

Hi I was asked at the UBports forum to report this here:

On a Fairphone 3 using VoLTE leads to following issues

• SMS cannot be sent (while receiving them works)
• Outgoing phonecalls have no ringing tone (but work somewhat)
• Some outgoing phonecalls are (or at least are presented as) still active even after stopping them
• Incoming phonecalls are not working, I only got notifcation messages afterwards from the provider that someone tried to call me

This behaviour was confirmed for UT 20.04-10 and UT 24.04-1

Switching off VoLTE in the cellular settings (or restricting connection type to 2G/3G only) everything regarding SMS and phone calls works alright for me.