Multiple householdId's among units controllable from one Sonos mobile app?

I have 3 Sonos units controllable from my Sonos Android app: A, B, and C. A and B return one householdId from http://<ip>:1400/info, but C returns a different householdId.

From the Sonos Android app (slightly abridged):

About My Sonos System

Controller
Version: 10.2 (build 50165071)

Sonos A
Play:1
Version: 10.2 (build 50165071)
Hardware Version: 1.20.1.601
Series Id: A200

Sonos B
Play:1
Version: 10.2 (build 50165071)
Hardware Version: 1.20.1.601
Series Id: A200

Sonos C
Play:1
Version: 10.2 (build 50165071)
Hardware Version: 1.20.1.601
Series Id: A200

Below are the two household IDs I observed. Of note, the strings only differ after the '.'

Sonos_K9Coj5AnNdwkpeGiArYtMHF4ug.6M_0OEa8aOhO-j2oZUMF Sonos_K9Coj5AnNdwkpeGiArYtMHF4ug.WOnnBPGSlfiyINzEybJL

$ curl http://192.168.5.33:1400/info && echo && curl http://192.168.9.42:1400/info && echo && curl http://192.168.5.71:1400/info && echo
{"websocketUrl":"wss:\/\/192.168.5.33:1443\/websocket\/api","playerId":"RINCON_7828CA92D6B201400","householdId":"Sonos_K9Coj5AnNdwkpeGiArYtMHF4ug.6M_0OEa8aOhO-j2oZUMF","groupId":"RINCON_7828CA92D6B201400:2486844229","apiVersion":"1.12.2","minApiVersion":"1.1.0"}
{"websocketUrl":"wss:\/\/192.168.9.42:1443\/websocket\/api","playerId":"RINCON_949F3E8AE0D601400","householdId":"Sonos_K9Coj5AnNdwkpeGiArYtMHF4ug.WOnnBPGSlfiyINzEybJL","groupId":"RINCON_949F3E8AE0D601400:1922741597","apiVersion":"1.12.2","minApiVersion":"1.1.0"}
{"websocketUrl":"wss:\/\/192.168.5.71:1443\/websocket\/api","playerId":"RINCON_7828CA92D67801400","householdId":"Sonos_K9Coj5AnNdwkpeGiArYtMHF4ug.WOnnBPGSlfiyINzEybJL","groupId":"RINCON_7828CA92D67801400:3241438112","apiVersion":"1.12.2","minApiVersion":"1.1.0"}

I expect all of these units to be in the same household, and thus have the same household ID, since they are all controllable from my Sonos Android app.

Solution

Player C may be joined to a different network. From the Control documentation:

Each household is represented by a householdId. The householdId is stable with one exception. The value will change if players are moved to a different network. For example, if a user moves some players from a household to a different network, the players that were moved will use a different householdId. If all of the players in a household are moved to a different network, the householdId will remain the same.

Turn off the router that Player C is connected to and join it to the same network as the others. See Connecting Sonos to a new router or WiFi network for details.