Upgraded to 3.0 – fields in user profiles not displayed

I’ve just upgraded to PIE 3 from PIE 2. Registration of new users works fine, collecting all fields in the form. However, for older users who registered prior to the upgrade, their profile pages do not show any of the extra fields (there’s a heading “Pie Register Registration Fields” immediately above the “Update user” button on the standard WP user page).

Similarly, if a user edits their profile via profile_pie, new users see all their fields, whereas old users only see the default WP fields.

As far as I can see, the data is still intact in the database for all users, with the same meta_keys for the fields : e.g. both old and new users have their address stored in pie_address_10 in the database. Why isn’t this being displayed to old users?