I think, there is a bug in SFOS implementation for Xperia 10 III of Phone App or the network subsystem or whatever.
Not only the random loss of audio is here, but also SMS cannot be sent without switching VoLTE off.
10 III running on previous 5.0.0.61 has the same issues.
Btw. jorvikku mentioned it in Release highlights: [quote=“jovirkku, post:1, topic:22916”]
Random loss of audio after phone calls is fixed or alleviated by fixing a crash in ngfd.
[/quote]
But evidently the problem persisted.
My Xperia XA2 work fine on the latest revision 5.0.0.67.