A user that is in LDAP, but never logged in, will be detected as a user by the CreateOrCommentHandler service when an email is received. While this is technically true, the unfortunate reality is that an error occurs on the creation of the issue as the user is not in the jira-users group. Users must be in jira-users before they can use JIRA.

The solution to this would be to detect the user is valid (done currently) and also test if they are in the group jira-users (not done). If not in jira-users then they should be auto added to the group - because they are now using jira.

The significance of this bug is that a user, not in LDAP, actually is better off then a user in LDAP. An unknown user is simply and correctly added to the JIRA directory with jira-users and everything works nicely.