Unable to add new users as Jira software board admin via board settings. Error: "Ug" is not a valid user

Issue Summary

Unable to add new users as Jira software board administrator via board settings.

Error:
"Ug" is not a valid user.

Steps to Reproduce

• Invite a new user to the Jira cloud instance.
• Try to add the new user as a board admin in any Jira software board

Expected Results

The new user should be added successfully to the board administrators field.

Actual Results

The following error message is seen upon adding the new user:

Workaround

Currently there is no known workaround for this behaviour. A workaround will be added here when available