Regardless of original or current start date, when you edit a Listening Rule, the start date in the rule builder reverts to the current date. The new default start date for the rule does not affect previously collected data. Earlier date ranges for the rule are retained and include the logic of the rule across the corresponding date range.
Example listening rule with Display Name "Testing Adobe" has earlier date ranges of 2/14/14 to 4/08/14 and 4/08/14 to present: