OK, I’m not familiar with it but a quick search doesn’t throw up any known issues with handling multicast, which as described in this really helpful post by @anupc is an essential part of the Mosaic (re)discovery process that surprisingly many consumer networking products, especially mesh, seem to have problems with.
One simple workaround for this problem is to get the IP address of the Bartók (from the front panel) and then input it manually (press the cogwheel top right in Mosaic while the wheel of death is spinning).
For me rediscovery usually takes 1-2 seconds max. It may be that your network processes multicast correctly but slowly?