Why we are not getting school association for some of the deactivated users?

Question

We have a lot of deactivated users. For some of the users, we are getting school associations but for some of the users, we are not getting schools. Below are the examples of 2 users. We need school associations for all the deactivated users.

This is one user(deactivated user) for which getting school association: Response from deactivated api

  "student": { 

      "birthDate": "2015-02-01", 

      "externalId": "S114730", 

      "grade": "03", 

      "graduationYear": "2033", 

      "studentNumber": "114730" 

    }, 

    "schools@odata.context": "https://graph.microsoft.com/v1.0/$metadata#education/users('2b4e43f7-f2fa-4597-b6ad-3195ed3ab80b')/schools", 

    "schools": [ 

      { 

        "id": "00e4f3e0-ad15-48fa-975f-353698bbbce6", 

        "displayName": "Hilltop Drive", 

        "description": null, 

        "principalName": "Charles Grisier", 

        "phone": "6194228323", 

        "externalSource": "sis", 

        "externalSourceDetail": "SIS", 

        "externalId": "28", 

        "schoolNumber": "28", 

        "lowestGrade": "KG", 

        "highestGrade": "6" 

      } 

    ] 

This is another user(deactivated user) for which not getting school association: Response from deactivated api.

    "student": { 

      "externalId": "S494882", 

      "grade": "03", 

      "graduationYear": "2033" 

    }, 

    "schools@odata.context": "https://graph.microsoft.com/v1.0/$metadata#education/users('284b3a3f-4048-41ac-9b03-83910b1e1e55')/schools", 

    "schools": [] 

  }