When importing TestNG results, labels are not being created on updated Tests

When importing TestNG results, labels are not being created on updated Tests. 

This happens via Rest API and UI.

The report file used is attached.

 Steps to reproduce:
1. Add a new label in the XML file, associated with an existing Test.

2. Import the results, using the TestNG endpoint.

3. Go to the Test:
Result: New Label is not present.
Expected result: All labels present.

Report:

Jira: