@tgodfrey the contact messages will be sent to the email of the collection owner.

Are you using a menu link or the Contact link on the header of the "Site skins" (see screenshot below)?
Can you please share a link to your site?

Thanks for your reply. I solved it: with two members, when I changed ownership to the second - a 'trusted user' - I did not configure access for that group properly. Subsequently, it seems that because the second member did not have appropriate access, the form defaulted to the only member who did.

When I gave the 'trusted user' appropriate access, the form displayed that user as recipient.