One option would be to ask the list owner if that submitter is a partner.
I see submits all the time with recips to link lists that are closed to submits or I know for a fact that they are not following the rules of some of the sites in the recip table. I delete em. No sense in wasting time trying to figure out what is going on. And I damn sure don't let a recip from a bigger list influence accepting a site that does not follow my rules.