Oh that’s great news, well at least there’s an easy way around it.
The usb to toslink isn’t very expensive but it does leave a nasty mess of cabling on my desk. The audio is great though. The details have been mentioned in a couple topics here in the past, starting I think a bit less than three years ago.
WH
FWIW, I gave up on the Phonak and went back to a Starkey ITC aid.
Of course, the new Starkey Genesis Al 24 uses a new (dumbed down) app and they changed the way they stream, so I can get full mute, but now dealing with BTLE connectivity and disconnects. Fortunately, I will be upgraded to the new Signature series when they hit Canada this month, which Starkey tells me has MUCH better Bluetooth connectivity and circuitry 
But that is for a new post 
Do you have Audio Lumity? L90?
I can confirm they completely mute. Whatever you are hearing is your natural hearing, combined with the possibility that the movement and the hearing aids are creating wind noise and you are picking that up with your natural hearing.
Just to confirm, the mute checkbox in Target is checked?
Trialing the I90 Sphere,
Yeah, when you mute the Sphere on AutoSense OS mode i can barely hear what around me. That don’t bother me, in fact that help me to hear alert sound when a trameway door is about to close or car honking around me !
Phonak could improve to allow the choose to mute 100% or not in target.
When streaming it’s different, the mute is 100% if activated via the mute button on the phone app ( or by the down volume button for 2 seconds if activated on target ) but does not persist when program change
so when the bluetooth stream end ( or i change track in spotify for example ) the hearing aid stop mute. There are the slider on the phone app to focus on the audio stream but i can still hear around me.
I wish Phonak allow us to have ( like Signa or Beltone/Resound i’ve tested / used to ) mute persist around program, and go out mute only when i want to !
That’s not how mine work. When I stream, Mute is the same as mute non-streaming. It’s about 90%+, but not 100%.
I stream every day (I listen to a lot of music that way), and almost always mute. I can still (faintly) hear external sounds.
What about it?
Honestly, I switched to Starkey because of that issue and the Starkey works as expected. I don’t like dumbing down of controls, and Starkey is bad enough…