When the standard email feed is queried via http://localhost/sdata/crmj/sagecrm/-/email this returns feed entries UNTIL any email is marked as deleted. If any email address is marked as deleted it throws an error with a stack trace (excerpt below):

java.lang.IllegalArgumentException: Timestamp format must be yyyy-mm-dd hh:mm:ss[.fffffffff] at java.sql.Timestamp.valueOf(Unknown Source)

This issue has been fixed in Sage CRM 7.3GA.