in a smartthings mesh, only one of the 4 units acts as the home automation controller for the zwave devices. it’s strange, but that’s how it seems to work.

a zwave network is itself a mesh. There is only ever 1 controller. If all 4 were zwave controllers you would have 4 zwave meshes.

It should be marked primary. Or you can just unplug them until your stuff stops working.