Running multiroom balenaSound without any internet connection

I am attempting to run balenasound multiroom on two raspberry pi 3Bs without an internet connection (I have removed the vc4-kms-v3d dtoverlay setting from the Device Configuration section for both devices as suggested). So, my first question is, should it be possible to start the multiroom system running without ever connecting to the internet?

More details, I would like to bluetooth connect from my phone to the master pi and sync the music to a client pi over a wifi router that is not connected to the internet. From what I understand, the the multiroom setup should work without internet connection, however, the only way I have been able to successfully start a session is with the wifi router connected to the internet to start. I am able to unplug the router from the internet after the system is running without causing any issues, however, if there is any hiccup in power to the router (which is unavoidably common unfortunately) I am unable to get the system working again without reconnecting the router to the internet (at which point the system fixes itself fairly quicklky). Furthermore, if the router loses power not only does the multiroom client device stop sending out sound but the master device also stops playing music despite apparently being still connected to the phone by bluetooth. I’m not sure whether the issue lies in the balena software or in how the router works.

I hope I’ve given enough details. Thank you in advance for any assistance. Balenasound is an amazing project that I’m excited to be playing with.