The search itself will not return any errors. However an Access Denied Error will be shown in the preview of the message if the user attempts to view the content of the message
The occurrence of the problem can be reduced by disabling Search Cache Permissions under Site Properties - Advance - Indexing
The problem happens when the Security Descriptor cache is cleared (due to the number of records in it hitting the max number, the age of the cache hitting the max age or after a restart of the Directory Service being restarted.
This issue has been addressed in the following releases available from Downloads:
Enterprise Vault 12.2.3
Enterprise Vault 12.3