Some Content IDs on API Response are null

This is the API Call we are directing to Taboola :

curl --location 'https://backstage.taboola.com/backstage/api/1.0/<acc-id>/reports/top-campaign-content/dimensions/item_breakdown?item_breakdown=item&start_date=2023-03-24&end_date=2023-03-24' \
--header 'Authorization: Bearer <token>'

From the API response we are receiving performance and other statistics data, but some content ids are sent as null.