Problem:
Incorrect name is displayed in Jabber for the logged-on user after they sign on.
This typically happens for either a new hire or, more often, an employee with a name change.
Example: Janet Boswell got married. After IT processed the changes and she could log on with her new name (Janet DeRuiter), her Jabber still displayed her name as Janet Boswell. No amount of resetting or uninstalling / reinstalling Jabber will fix this issue.
Solution:
Make sure the user's display name is correct in Active Directory.
This is where Jabber gets its display name from.
Changes in Exchange and Vision update AD. For some reason, these values got reset back to Boswell, Janet after I saved them.