In Moodle LMS, the user interests are linked to tags. We do the same in the Moodle app, but in the WebService we only receive the interests names, not the tag related data like tagid or tagcollid. This means that, if a tag is in more than one collection, the app displays an error when the user tries to view it: Tag is in more than one collection, please indicate one.

IMO the WebServices should also return some data to identify the tags, like the tagcollid. I don't know if all the tags in a user profile will always belong to the same collection or not.

The WebServices used by the app are:

core_user_get_course_user_profiles
core_user_get_users_by_field
 
I guess core_user_get_users should also be modified because it returns interests too.