This is not limited to Bluetooth in any way. In pavucontrol I can see Firefox outputting audio when on AliExpress even though nothing is playing. The uBlock filter fixed it.
what filter ?
To block the scripts open the uBlock dashboard, select My filters, and add:
! AliExpress AWSC fingerprinting scripts
||assets.aliexpress-media.com/g/AWSC/uab/*/collina.js$script,domain=aliexpress.com
||assets.aliexpress-media.com/g/AWSC/fireyejs/*/fireyejs.js$script,domain=aliexpress.com