Roles and Permissions don't carry over when a Space is Exported then Imported

(Bug, New , Priority: Unknown Priority, Test Status: No automated tests yet , Reported By Bad Link: Thing 3y284oe not found, )
Summary: Export a Space where some folks have custom roles, and some Things have permissions granted to specific individuals. Then Import it.
The pre-populated users of the space (which are some sort of stub, IIRC) all have their previous Roles, and are correctly associated with Thing-specific permissions they held previously. However, when the original user is invited to the space, it creates a new user record in addition to the pre-populated one, with the following effects:
  • The user appears twice in the Sharing > Members tab
  • The newly created user does not have its previous Roles
  • The newly created user is not referenced in any permissions that had previously been granted specifically to them
It's possible this is an un-bug if there's something specific about the new invite that I needed to do and didn't, but ownership did seem to transfer correctly - Things which were created by someone in the original space registered as matching _creator with that person in the new space.