No converter available for 'state_relay' on ...

What happened?

Scenario:

• Defined one group
• Added just one Busch-Jaeger Relay-Switch
• Pressing ON, OFF, or Refresh on the group's expose page has no effect at all. An error is reported: "No converter available for 'state_relay' on"

Sounded like https://github.com/Koenkk/zigbee2mqtt/issues/24792

What did you expect to happen?

Switching the relay via the group should work. It did in the past, though I cannot say in which version.

How to reproduce it (minimal and precise)

See above

Zigbee2MQTT version

2.13.0

Adapter firmware version

20250321

Adapter

Texas Instruments LAUNCHXL-CC1352P-2

Setup

In a container on Kubernetes ARM64

Device database.db entry

{"id":16,"type":"Router","ieeeAddr":"0xd85def11a10016e1","nwkAddr":6526,"manufId":4398,"manufName":"Busch-Jaeger","powerSource":"Mains (single phase)","modelId":"RM01","epList":[10,18],"endpoints":{"10":{"profId":49246,"epId":10,"devId":2064,"inClusterList":[0,4096],"outClusterList":[4096,3,6,8,4,5,768,25],"clusters":{"genBasic":{"attributes":{"modelId":"RM01","manufacturerName":"Busch-Jaeger","powerSource":1,"zclVersion":1,"appVersion":1,"stackVersion":1,"hwVersion":0,"dateCode":"20161209","swBuildId":"1.2.0"}},"genOnOff":{"attributes":{}},"genLevelCtrl":{"attributes":{}}},"binds":[{"cluster":6,"type":"endpoint","deviceIeeeAddress":"0x00124b001ca16690","endpointID":1},{"cluster":8,"type":"endpoint","deviceIeeeAddress":"0x00124b001ca16690","endpointID":1}],"configuredReportings":[],"meta":{}},"18":{"profId":49246,"epId":18,"devId":0,"inClusterList":[0,4,3,5,6,8],"outClusterList":[],"clusters":{"genBasic":{"attributes":{"hwVersion":0,"modelId":"RM01","manufacturerName":"Busch-Jaeger","powerSource":1,"zclVersion":1,"appVersion":1,"stackVersion":1,"dateCode":"20161209","swBuildId":"1.2.0"}},"genOnOff":{"attributes":{"onOff":0}},"genLevelCtrl":{"attributes":{"currentLevel":254}}},"binds":[],"configuredReportings":[],"meta":{"scenes":{"0_80":{"name":"Off","state":{"state":"ON"}}}}}},"appVersion":1,"stackVersion":1,"hwVersion":0,"dateCode":"20161209","swBuildId":"1.2.0","zclVersion":1,"interviewCompleted":true,"interviewState":"SUCCESSFUL","meta":{"configured":"0.0.0"},"lastSeen":1785568352143}

Debug log

No response

Notes

Using '/app/data' as data directory
Starting Zigbee2MQTT without watchdog.
[2026-08-01 09:08:57] error: z2m: No converter available for 'state_relay' on 'bathroom_mirror': ("")
[2026-08-01 09:11:57] error: z2m: No converter available for 'state_relay' on 'bathroom_mirror': ("OFF")
[2026-08-01 09:11:58] error: z2m: No converter available for 'state_relay' on 'bathroom_mirror': ("ON")
[2026-08-01 09:11:59] error: z2m: No converter available for 'state_relay' on 'bathroom_mirror': ("")

Reproduce the group control failure with one Busch-Jaeger RM01 relay and inspect the group expose handling and converter registration responsible for state_relay. Compare the behavior with the linked issue and test ON, OFF, and Refresh through the group page. Done means all three actions work without the “No converter available” error.