Thanks, Minty; that's great. I've reported it in the app to add to the pile; hopefully they'll fix it soon. It's not too bad for us, so can live with it until then. Just glad to know it's not anything I've done!
I've had the same error the past three days. Like the OP we didn't change anything else. Even opened up an old DB version with it's old Backed from 2 years ago and had the same issue. Not seen it before this week.