iCloud Drive storage on iPhone is showing greater usage than I have on iCloud

My iPhone storage (64GB iPhone X) shows 10.78GB of usage by iCloud Drive. However when I view iCloud Drive in Files there are no downloaded docs (checked in folders, checked in recently deleted). My iCloud Drive usage on iCloud is 79.4MB which is as I'd expect.

I'm concerned that the storage being taken up on my iPhone purporting to be iCloud Drive is actually malware, perhaps in the form of hidden files, but can't find anything. Any recommendations please?