Bugzilla importer fails when importing existing users

When importing a bugzilla project into a Jira instance which already contains usernames equivalent to those in the bugzilla project, the import fails when attempting to match the existing usernames.

Note that the Jira instance already contains projects, but not the same project that is being imported from Bugzilla (i.e. project being imported is a NEW project); however, jira users in the existing Jira projects have the same usernames as jira users existing in the bugzilla project being imported.

This issue occurs regardless of whether the "Reuse Existing User Accounts" option is checked or not during the import.

I've run some tests with dummy user accounts (i.e. creating the same user account in both Bugzilla and Jira), and have noticed that if the offending user in Jira is deleted, the importer succeeds (i.e. the importer can simply create the new jira user, and doesn't need to worry about an existing jira user with bugzilla account name). The problem is that the existing Jira users all have issues in other Jira projects, and thus cannot be deleted – the existing users must be re-used by the Bugzilla importer.

All existing Jira users are members of the "jira-users" group.

See the attached error.txt for an instance of the error thrown for each user conflict encountered (i.e. each time the bugzilla importer attempts to import/reuse an existing jira user)