MQTT - Auto discovery (/config) cause sensor "last_updated" to change

I do not know if this is the intended behavior, but I just noticed that the “last_updated” time of a MQTT sensor seems to be updated whenever a auto discovery message (i.e. "homeassistant/sensor//config …) is received.

I have several MQTT devices with auto discovery that I try to monitor for stale sensors, and this behaviour does basically mean that I’ll have to revert from auto discovery to manual configuration of each sensor.