If using a version of Authentication services prior to 4.1.2.23060 then this is a known defect:
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Defect 717481
* vasd: Move uid conflict code to checking the pwent table.
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Upgrade to a more recent version of Authentication services containing the defect fix in order to avoid these false UID conflict messages.
The latest version of Authentication services can be downloaded from the following link:
https://support.oneidentity.com/authentication-servicesIf you are unable to upgrade, this command can also be used to remove the duplicate entries from the QAS cache file:
# printf '.timeout 5000\ndelete from user_posix where userkey not in (select userkey from user_ad);\n' | /opt/quest/libexec/vas/sqlite3 -header /var/opt/quest/vas/vasd/vas_ident.vdb
Essentially this command will look for user_posix entries without a corresponding user_ad entry and delete them.