Duplicate emails are getting created during event import. Some of these duplicates will be zero bytes in size or contain little or no content.
CA Data Protection 15.2
When the limit for maximum number of objects per MAPI session is reached, Event Import is unable to delete mails in Exchange and duplicate emails are getting created.
This issue is addressed by FIX:SO00617 (incorporating Server_15.20_HF0149 and Server_x64_15.20_HF0150). After this fix is applied the duplicates are avoided by restricting the number of Exchange objects opened per MAPI session (this is hard-coded to 200 objects).