Archived items are not recalled from Enterprise Vault if the Sharepoint web application has been extended. Rather than the full content of the archived item being displayed, only the word EVSTUB is shown.
When a Sharepoint web application is extended, a new virtual directory is created in IIS in addition to the existing virtual directory for the web application being extended. The Enterprise Vault setup program and the SharepointFeatureSetup.exe utility are unable to detect this additional virtual directory, and therefore do not configure its web.config file to include the Enterprise Vault HTTP Module that is necessary to facilitate the recall of archived items.
This issue has been resolved in the following release:
Enterprise Vault 9.0.4 Cumulative Hotfix 5 Release