Mysteriously fixed itself about a week ago for me, Fraser had said it looked like something to do with updates/cloud related. Im back on the latest firmware all good!
After looking into it personally a bit more I would say it's highly likely to be a cloud update. As far as I can tell NG have auto updated people to the mentioned firmware version there (we originally completed the DumaOS changes for that a very long time ago) but didn't mention they were doing it and so I think it's trying to use a cloud update it can't use or isn't using the one it should now be using. I've given my findings to the team so it should hopefully be a quick update once they identify the specific cause.