If a target pod was manually promoted or the SRA was unable to eradicate the undo pod (for instance if safe mode was enabled) a test recovery cleanup will fail as the pod will not be able to be demoted due to the presence of an undo pod.
Failed to delete snapshots of replica devices. SRA command 'testFailoverStop' failed. Array operation failed: "PureRestException: HttpStatusCode = 'BadRequest', RestErrorCode = 'InternalError', Details = '["context":"SRM-podB","message":"Cannot demote pod because the associated undo-demote pod has not been eradicated.","context":"PATCH","message":"https://flasharray-m20-2.purecloud.c..._quiesce=False"]', InnerException = ''". Array operation failed. Please see logs at /srm/sra/log/testFailoverStop_2020-08-17-16-35-16-3662578-45c6e077-144a-4f5b-8c8d-f46c61a40ecb.log.
To verify, login to the target FlashArray and look under Destroyed and Undo Pods and see if there is a destroyed "undo" pod there for your target pod. If this exists, the test recovery cleanup will not be possible until it is fully eradicated.
There are three reasons that the undo pod might still exist: