This is likely due to configured subscriptions not having any cost associated to them.
The reason why the Azure Subscription is missing the Cost Category field is because the Cost Center field populates for Azure Subscriptions from the Enterprise Agreement bill.
If a subscription does not have any cost or spend associated to it, the information is never written to the EA bill. This means that the Cost Center value cannot be ingested from the bill, leaving the Cost Category field empty on the CloudHealth side.
NOTE: The Cost Center will be derived from the Azure EA billing data and Azure doesn’t provide cost center information for the Reservation Orders. This is the reason they fall under No Cost Center.
For more Insights refer below articles: