Start method for Call sometimes reports "Couldn't start the call: Unhandled response 'VOICE CALL: BEGIN ..."
It seems after the first call, I always get this:
purism@pureos:~$ sudo mmcli --call 5 --start
error: couldn't start the call: 'GDBus.Error:org.freedesktop.ModemManager1.Error.Core.Failed: Couldn't start the call: Unhandled response 'VOICE CALL: BEGIN
VOICE CALL: END: 000027''