Attempting bulk create issues (through a CSV file) using email addresses for custom user picker fields results in error

Issue Summary

Attempting bulk create issues (through a CSV file) using email addresses for custom user picker fields results in error.

Steps to Reproduce

1. Press the global Create button.
2. In the Create issue dialog, press the Import button to move to the bulk Create screen:
3. Upload a CSV file, the file must contain email addresses to map with custom user picker fields.
4. Map the email data from the CSV files to the a custom user picker field during the import process.
5. Finish the import process.

Expected Results

Th issues are created, and the emails mapped result in the corresponding user set in the user picker fields.

Actual Results

An error in shown, indicating "Issue can't be created due to the error/s [ User '<email address>' was not found in the system. ]"

Workarounds

• Use the AAID instead of the email.
• Use the full External System Import option instead of the Bulk Create.