Just upgraded to Drupal 7.54 and now when a user account is saved, any other users (other than admin 1 user) are unable to view or update the custom fields associated with the user account. They just see the core fields. The admin 1 user is still able to see all fields.
When the updated user account is viewed or edited by any other user than the admin 1 user (they do have 'administrator' role assigned), they only see the following fields:-
I have disabled modules that act on fields, such as Field Permissions and Conditional Fields, but still getting this behaviour.
Any ideas why this could be happening would be much appreciated!