Domoticz errors flooded: MQTT: Exception (GetValueFromTemplate): Type is not convertible to string! (Template: value_json[overload_protection]) 2.11

[gbonny1982]

What happened?

I'm running Zigbee2MQTT in a Docker container. After the update from 2.10.1 to 2.11 there are serious issues regarding the communication between Zigbee2MQTT on one hand through Mosquitto (latest) through Domoticz 2025.2 on the other hand.

The Domoticz error log is flooded with after half a minute:
2026-06-02 20:37:59.415 Error: MQTT: Exception (GetValueFromTemplate): Type is not convertible to string! (Template: value_json[overload_protection])
..all the way..

I've tried rebooting Domoticz, then Mosquitto and then Zigbee2MQTT. No solution.
Then I stopped Zigbee2MQTT and the error messages stopped. I started Zigbee2MQTT again and the errors continued to flood. I reverted to version 2.10.1 and the system is working again normally without error flooding.

I think HomeAssistant had issues as well, with loosing track of Zigbee devices. (I have HomeAssistant & Domoticz connected to Mosquitto and both read from Zigbee2MQTT)

What did you expect to happen?

No errors like the version before.

How to reproduce it (minimal and precise)

reinstall latest version 2.11

Zigbee2MQTT version

2.11

Adapter firmware version

ZStack3x0 - Revision: 20240710

Adapter

zstack

Setup

docker container on ubuntu 24.04.4 lts up-to-date.

Device database.db entry

No response

Debug log

No response

Notes

No response

[arjanvanleent]

Same problem over here