The “disconnected” message is likely innocuous. There are three messages you are likely looking at - “disconnected”, “inactive”, and “active”.
The disconnected message indicates the hub’s connection to the cloud was closed. However, there is a lag in reporting so your hub likely disconnected and quickly reconnected but that message is still generated.
As you can imagine, receiving a “Your Hub is offline” message every time “disconnected” is reported would become quite annoying and would also likely be inaccurate. Instead, we wait ~5 minutes after your hub disconnects before reporting that your hub is inactive.
You will only get an “active” message if your hub reported “inactive” and then came back online.