I've just done so now, but will be raising this with the MTA dev team.
When it occurs, the MTA console says the following:
[12:41:45] ERROR: Could not start HTTP server on interface '(null)' and port '22005'!
[12:41:45] Server stopped!
[12:41:45] Closing SQLite3 database
Press Q to shut down the server!
If you noticed an outage earlier today, it's since been resolved.