It's the Bluetooth; when Bluetooth connects most hearing aids reduce the environmental volume slightly so you can hear the streaming content. Some app has started to play audio (perhaps silently). I notice it on some websites.
How much HAs reduce environmental sounds when streaming is configurable by the way, but only by the audiologist if you don't have your own programmer. I don't like the effect and prefer to just turn down the volume manually.
How much HAs reduce environmental sounds when streaming is configurable by the way, but only by the audiologist if you don't have your own programmer. I don't like the effect and prefer to just turn down the volume manually.