Invalid event type error in logs

[zylxpl]

Some errors spoted int the logs
Logger: homeassistant.components.mqtt.event
Source: components/mqtt/event.py:190
Integration: MQTT (documentation, issues)
First occurred: 17:38:21 (1 occurrences)
Last logged: 17:38:21
Invalid event type for event.shelly_1_salus_button_0 received on topic shellies/shelly1-8CAAB548291D-salus/input_event/0, payload {"event_type":""}

Device is sending periodical updates with empty event_type field which is nor correctly handled.

[bieniu]

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