Updating Memberships breaks Relationship Type setting

To repro:
1) Create a Membership Type
2) Set a Relationship Type on that Membership Type
3) Add a contact with the membership.
4) Add a contact with that relationship to the contact with membership.
5) Change the Membership Type's name
6) Review the Relationship Type - observe that it's been unset
7) Click on Edit, observe a message saying that it cannot be edited.