civiMail checksum token uses deleted version of duplicate records

We've seen several cases of duplicate contacts not being handled correctly with the checksum token.

Steps to reproduce:

• create 2 contacts with the same email
• delete one of them (mimicking the real-world process of deduping)
• then do a civimail message that includes that contact, and uses a checksum token to a profile page

The resulting tokenized link will produce a profile page filled with the deleted contacts details. I'm not sure if the order of the contacts matter... but this behaviour has been noted several times in our mass-mailings.