You are the TAE for an Agile project which has six sprints for the current release. Sprint five is underway and the automated regression suite is due to start later today.
You have re-examined the results from the automated regression runs for the past four sprints. You notice that two test cases both reported a pass for sprints 1 and 4 but a fail for sprints 2 and 3. The failures have gone undetected and are therefore unexplained. Both test cases are closely coupled with other tests in the suite.
What course of action SHOULD you take?