From deymo:

"From the BrilloSync stage, it looks like the builder grabs the latest master at the time you run that, but I couldn't find any pinned manifest (like in cros canaries).
https://uberchromegw.corp.google.com/i/internal.client.brillo/builders/bbuildbot/builds/3457/steps/BrilloSync/logs/stdio

Can we somehow add the ArchiveManifest() to the bbuildbot so we can repro it? That wouldn't help in this case, but might help in the future."