🚀 go-pugleaf

There's a similar problem with sites at Bristol.  For example,
uk.ac.bris.cs is a valid Janet mail site but uk.ac.bris get mapped to
bris.ac.uk@uk.ac.aucc too soon resulting in the address
cs.bris.ac.uk%bris.ac.uk@uk.ac.aucc.    As Jim says, the way round this is
to remove the janet.chn entry that causes it.

I then explicitly put the entry back by appending it to local.dom:

#
# bristol corrections
$+@bris.ac.uk	$2%uk.ac.bris@aucc.ac.uk
$+@bristol.ac.uk	$2%uk.ac.bristol@aucc.ac.uk

A similar thing should work for Manchester.