[Error] user-identifier-type not working properly

Hi! I'm posting completions correctly by using Email as user-identifier-type, ONLY when the given user has EmployeeId filled. If the user has the employee-id as null, it doesn't work, no matter I'm specifying the user-identifier-type as Email.

I know, you can think: "Yeah, this guy is doing a wrong request"
My answer is: "No, I think I'm not. You have the necessary information below"

I've tested it by using your swagger, via Postman with my own credentials and via direct integration in our code. It doesn't work, we have always the same error.

You can reproduce with this information (I'm not sharing any authorization token).
I give you permission to test it out

Method: POST
Endpoint: https://api.betatest.degreed.com/api/v2/completions
Body: {"data":{"type":"completions","attributes":{"user-id":"[email protected]","user-identifier-type":"Email","content-id":"pack_level_ar_a1","content-id-type":"ExternalId","content-type":"Course","completed-at":"2023-01-01T00:00:00.000Z"}}}

Can you, please check why you cannot POST a completion using the user-identifier-type Email if the user has no employee-id?

I'm waiting for your answer

Thank you