Forgetting audio zones

I’m experimenting with two roonservers right now, my long-term Windows NUC and a new SonicTransporter. Both exhibit a strange behavior: they sometimes forget endpoints, when I go into audio setup they are in the list but require enabling. Mostly this is for Meridian gear, but I think it may have happened with the MicroRendu as well. Can’t swear to that, have had other unrelated problems.

Just now, I had a particularly intriguing situation. Using the SonicTransporter, I had connected from a Windows 10 system, reminded it of the endpoints, and started play on the 818. Music is streaming. I then pick up the iPad for some purpose, and it shows the Select an Audio Zone. The zone selector shows it has forgotten the endpoints. So on the iPad I go into Audio Setup, enable the three Meridian zones, and when I do that the audio is interrupted (was playing fine in the meantime, even though the zone selector did not remember it existed). I hit play again, and it works fine.

Now, while I was writing this, just a few minutes, and I looked at the iPad – it has forgotten the endpoints again, shows Select an Audio Zone.

The current configuration in detail:
An Eero wifi node connected into a switch.
The SonicTransporter connected into the same switch.
818 and MicroRendu connected into the same switch.
One MS600 and a SonicOrbiter connected into other Eeros.
Another MS600 connected to a wifi dongle, on the same Eero wifi mesh.

The Windows server is connected into the same switch as the other stuff, still running but not active for Roon. I’ll try shutting it down and see if it changes anything, maybe they interfere over the network even when not active…