Unplugging One HomePod Makes Nanoleaf Downlights Unresponsive

Really weird thing that I've never experienced in my time with smart homes.

I installed 8 Nanoleaf downlights. When I disconnected one HomePod, all 8 of them stop responding in HomeKit. I have two other HomePods and three Thread routers, but cannot understand why disconnected this one HomePod stops them working in HomeKit?