While trying to open the Offer letter from the Offer letter Correspondence section of the Application , you might see the Warning message at the top of the Offer letter window that "Some attachments may have been deleted as part of the entity process"
SAP SF BiZx Recruiting
This the expected behavior , based on the settings selected at the time of Deletion of attachment
In manage recruiting settings, there were configurations which control the attachment (attachment related configurations are removed in b1805 release ) and correspondence (under Delete of correspondence section) when candidate is purged.
Based on configuration selection at the time of deletion, there might be chances where attachments are deleted but not from the correspondence.
In this case, when an operator views the correspondence, the warning message is shown.
KBA , LOD-SF-RCM-CAO , Candidate Offers, Offer Letters , Problem