MQTT entity shown as unavailable while its log is showing updates

While trying to introduce my first set of Zigbee devices (door sensors) via Zigbee2mqtt, I end up with devices and their entities showing up in HA but all entities being unavailable. The strange thing is that all information is properly transferred as can be seen in zigbee2mqtt, mqtt-explorer or even the log for that entity.
A picture may explain it best. The sensor entity is showing the error “This entity is unavailable” and no data in the history. However, the logbook on the right hand side does show updates when opening or closing the sensor.

This post may be related to this one, but also different in that it relates to the issue arising from the installation.

I assume I am making a silly mistake somewhere but cannot figure out the root cause based on any forum topic I came across. Any suggestion would be greatly appreciated.

The situation automagically resolved itself. Might have been related to zigbee2mqtt issue.