On attempt to create a staff member the task Create the user account with the username "firstname.lastname@example.org" fails with the error:
The username length exceeds 20 characters.
This is software issue PPA-2846: staff member user name longer than 20 characters is not supported in Plesk Automation.
This issue is planned to be fixed in future product updates. Please avoid using user names for staff members exceeding 20 characters in length.