Assignee User Picker is not showing the Users correctly when Creating a Test Execution from a Test Plan using Jira's Create Issue Dialog

Description
Assignee User Picker is not showing the Users correctly when Creating a Test Execution from a Test Plan using Jira's Create Issue Dialog.

Right now, after the dialog is opened, Xray is adding a User to the Assignee Picker, the user selected is the one assigned to the most Test cases within that Test Plan.
For instance, if the Test Plan has 3 Tests and User A is assigned to 2 Test cases and B to 1; Xray will try to define User A as the Assignee of the Test Execution being created.

Eversince Jira's Data Anonymization Enforce, there were changes on the New User Account Keys, when it started being JIRAUSERXXXXX. From there, Xray, in user pickers, stopped using User Keys and started using User Names.

Pre-conditions
When creating the Test Execution from the Test Plan, there must be some Fields defined as Required to ensure that the dialog you see is Jira's

How to reproduce

1. Create a Test Execution from the Test Plan;
2. Try to select an existing User

Actual result/Attachments
The user is not correctly suggested.

Expected result
The user is suggested.