Currently in RE 7.95 when you merge a constituent record, the Import IDs of Membership, Education and Action records are reset to RE default values and the date added is reset to the date of the merge. This causes a major problem for updating the Membership or Education or Action records through Import because the Import IDs are lost. In addition the history of the date the record was added is also lost.

There is a KB article that describes the problem only for the Action records: 

https://kb.blackbaud.com/articles/Article/98483

If this could be easily fixed it would save a tremendous amount of resource and preserve data integrity.