The iPhone's sound volume to be minimized when the BTT remote app launched.
Even I increase the volume with the button on the iPhone on any view of the app, it immediately and automatically decreases.
I know my cuurent BTT version is not the latest, but I think it occurs on BTT "remote" and could not related with BTT itself.
I don't know why but it always occured.
iPhone SE iOS 13.3 (latest)
BTT remote 2.3.1 (latest)
Mac OS X 10.11.6 El Capitan
In the BTT Remote settings under "General" you can disable the "Volume Buttons" setting. Afterwards it will allow you to change the volume again but you won't be able to trigger BTT actions using the volume buttons anymore.
Thank you, it works.
But if I want to use volume buttons on BTT remote, how could I manage with its curious behavior? The problem occurs regardless of whether there are or aren't volume buttons action on BTT of the Mac.
Anyway, currently I won't use volume buttons and I can disable it so it's not an issue for me.