The Sent Email record associated with a Suggestion record contains a different Approved Email Template than is specified on the Suggestion record.
The Email_Template_ID_vod field on the Suggestion object references an Approved Document that is not valid. If this field is populated with an invalid Approved Document Id, the standard Send Email interface is displayed, and users can select any Approved Document.
Ensure that the Approved Document referenced in the Email_Template_ID_vod field is valid when creating Suggestion records.
CRM Help Documentation: Suggestions