Sending/receiving a contact in Outlook 2003

When I attach a contact to an email and send it to someone on our domain, it comes through fine. But if someone outside sends me a contact, it comes through looking like a forwarded email attachment and nothing but the contact name and its notes. No address, phone number, nothing.
We don’t have a filter blocking Contact attachments that I know of.
What’s going on?

Thanks for any help or insight!