I conducted a fresh reinstall and database build after Roon Support diagnoses my database was corrupt.
UPDATE: after two full days following a fresh reinstall and database build, the sound I provided in the video is still not there. Perhaps the sound was connected to the corrupted database in some way.
Hopefully when future customers explain the unusual sound their Nucleus is making, my example can help Roon Support better troubleshoot the issue and even possibly anticipate database failure.
I will update this ticket if the sound returns.