This happened here: https://kojipkgs.fedoraproject.org//packages/fonts/f27/20171106163600/data/logs/build.log

1) MBS reused all the components from previous module build.
2) MBS tagged them to final tag and -build tag
3) (Unrelated) KojiRepoChange was received right after we requested the tagging.
4) KojiRepoChange "done" handler checked that all the components are COMPLETE and just marked the build as "done", but we still did not receive msg from Koji that components are properly tagged.
5) pdc-updater got that "done" message and tried to get list of all RPMs in final Koji tag.
6) Because the Koji still did not finish with tagging the components into final Koji tag, pdc-updater stored only some RPMs to PDC.
7) Pungi did not include all rpms in the compose
8) sgallagh is sad.

Following patch could make sgallagh happy again, but untested:

http://jkaluza.fedorapeople.org/mbs-tag-reuse.patch