Hubble's_law pdf showed up in save dialog file name as " 's_Law " making this the second time I have seen this error of leaving off characters before " 's".
Topic on Talk:Reading/Web/PDF Functionality/Flow
Thanks for reporting.
Thanks for reporting this. We were also able to reproduce this and filled the following bug: https://phabricator.wikimedia.org/T171747
This has been resolved in production. Thanks for the report!