Shelly device on signal reverts to off after about 15 second

Unprovoked, a Shelly1 that I use to power several Sonos amplifiers stopped working. The behavior was that an ON command was followed by the device turning off after a few seconds. The event log was not helpful. After looking for a trigger or some other explanation, and finding nothing, I resorted to reloading plugins - 1) MQTT Connector, 2) MQTT Broker, and 3) MQTT Shelly. It fixed the problem, but unfortunately, as I did all three reloads without first checking, I don't know which one(s) fixed the problem.
This error condition was 5 days ago, and has only occurred this one time.

Code: Select all

2023-03-24 20:24:01.125   ShellyMQTT   sent "b bOffTV - AudioSonos1..5 MQTT" on
2023-03-24 20:24:04.314   ShellyMQTT   received "b bOffTV - AudioSonos1..5 MQTT" off

Unrelated question: I'm using Shelly1 controls to manage wall outlets with Indigo. Am I not using the MQTT Broker plug-in?

It sounds like the device just crashed and rebooted itself, or it hit a power limit if you have one defined. The "received" log messages would come directly from the MQTT Broker, and therefore from the device itself.