Unusual issue with a branded (looks to be iptvsmarters) android app.

Beelink box connected via HDMI to TV which outputs digitally to a Yamaha soundbase.

Main issue is sound levels are fine with a broadcasting channel but if I select a channel that's 'off air', sound is at full blast.

Anyone encountered anything similar?

More minor issue is that on the apps internal player, sound is intermittent - if I select play with VLC or MX, there isn't an issue - anyone help?

Service is Solaris Streamz - good range of channels but sound will see me let sub expire.