Liu: 

builtin MacOS archive tool also reports 674.

since Google archiver, and built-in tools on all major platforms report 674 files; it looks like 7zip might be the outlier here [note also that 7zip have their own format].

Unless it can be shown that Python and all of the archivers showing 674 have a common bug, I think there's not much we can do, as Python seems to be reading the archive in a defacto standard way.