Project Manager only copying nested sequences, not main sequence.

I have a project (577.prproj) with 24 nested sequences, many assets, and one main sequence (577).  Using the project manager to archive the project to networked long-term storage, I’m only given the option to check the nested sequences.  The main sequence is not detected.  I’m on Windows 10 Enterprise, Premiere Pro 26.0.0 (build 72).  There are no errors reported.  The problem was clear when I saw that the 577 Masks directory was not included in the archive, but because the 577 sequence was not available in the Project Manager dialog I was on the lookout for problems.

Workaround: I’m using the file system to copy the working directory to archive, but that won’t capture files from the project that aren’t in the working directory.