This in my understanding generates failure reports for any forwarded
mail including any mail to lists that do not completely rewrite From:
(including this one mailing list)
- even if DKIM is preserved and valid, such mail won't generate
aligned SPF pass
unless you have better explanation of that section...
fo is for debugging. If someone defines fo for their domain and gets a
bunch of failure reports, they get what they wished for. The mailing
list itself does not have to process those failure reports, nor is the
mailing list penalized for it.