Issue Summary

When Using API for Audience Spesific pages, adding components to the page subscribers and subscribing to the Individual components using Update Subscriber API endpoint results in unexpected behavior when exporting those users via CSV. After the update, it makes the "Email component subscription" column blank in CSV which we export from export users. 

Steps to Reproduce

1. Add a user in Audience specific page and do not add the user to any group
2. Using API add components to the user
3. Now Add subscription using Add subscriber endpoint 
4. Now use Update subscription endpoint and try updating the component list. 

Expected Results

It is expected to list all the components under the "Email component subscription" column in exported CSV 

Actual Results

The column is blank

Workaround

Remove the Subscribers and Add them again using Add subscribers endpoint.