Square Loyalty API returns Loyalty Account with CustomerId Null

We are receiving weird response from Square Loyalty API when we search for a loyalty account with a Phone number. The result has square loyalty account but there is no customer_id

Question 1: In what scenarios can this happen?
Question 2: How can we associate a customer account with a loyalty account when this happens?

  "loyalty_accounts": [
      "id": "52014fa0-0dcd-48ac-97d6-4c057f0001f8",
      "mappings": [
          "id": "92415d1d-5b00-43d2-844b-35da30820e55",
          "type": "PHONE",
          "value": "+13***********",
          "created_at": "2017-10-25T01:01:45Z"
      "program_id": "760029f1-9292-4fae-8cc1-f4a471a66694",
      "balance": 1,
      "lifetime_points": 1,
      "enrolled_at": "2017-07-18T19:56:17Z",
      "created_at": "2017-10-25T01:01:45Z",
      "updated_at": "2019-03-05T21:05:35Z"

Checked in with our Loyalty team. There is a bug on our side where if you do a “Merge All” and more than one customer that is being merged has a loyalty account, it could leave the loyalty account unmerged. If you do manual merges, this shouldn’t happen, but they are working on fixing the merge all issue.