I've never had an issue with these zip files before, and they are not corrupted in any way.
Extracting the zip files fixes all problems.
Repackaging the files back into a zip folder recreates the same problem, even when creating a new archive.
Even redownloading the zip files does not fix any of these issues.
None of the extracted files have any errors.
The zip files are sourced from Bandcamp, both working and non-working downloads.
The music contained in these files are .flac files.
There appears to be no correlation with file size regarding the issue.