When can idEnterprisesAdmin be an empty array for enterprise account?

One of our customers claims to have an enterprise Trello account, but when we call the /1/members/me API using the admins token it returns idEnterprisesAdmin as an empty array. In what cases is it possible to have an empty idEnterprisesAdmin for an enterprise account?

Note - idEnterprise is being returned as part of the response.

Can you also please provide documentation for the following API response fields - idEnterprise and idEnterprisesAdmin?

Any update would be greatly appreciated. :pray: