As with so many interim builds, in the past, there are many left over items from previous OSs. I am sure that when rewriting, the programmers start with the original files and amend accordingly. When sfc scannow is run, it checks the files against the new Dbase and when it encounters files not listed ( yet) chalks them up as corrupt.
This is particularly prevalent in Windows X, which , I believe, was intended to be the cancelled Windows 8.1 update 2. If you doubt this, you will find references to Windows 8.1 in the Local group policy and registry.
My deduction only!
I find everything running pretty much as it should, so I do not see it as a bug.
FWIW. If anyone still has a copy of the Windows 8 Public preview, you will find the same occurrence there.