There is an object field populated on a document with a value. When a user clicks on the value, instead of taking the user to the object record under the tab configured for the corresponding object, it takes the user to the object record under the Business Admin area in Vault.
The user either does not have the permissions needed to access the object tab, or the object tab was setup as an object type tab rather than a base object tab.
The user would either need to be granted access to the object tab through their permission set or a base object tab would need to be used rather than an object type specific tab for the corresponding object.
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Vault Help Documentation: Configuring Custom Tabs