FWIW, If you go to https://datatracker.ietf.org/doc/draft-ietf-blah-blah-blah/email/ you can see what the datatracker thinks the aliases expand to. draft-ietf-blah-blah-blah.all@xxxxxxxx is intended to work, so the advice is good. Clearly something is currently broken. https://trac.tools.ietf.org/tools/ietfdb/newticket is a good place to go to report problems. Adrian