Postcondition failed for step UpdateDefaultRWConcern error

Using ops manager to create rep.set. Encountered the following error.

<ReplicaSet_1> [15:29:06.968] Plan execution failed on step UpdateDefaultRWConcern as part of move UpdateDefaultRWConcern : <ReplicaSet_1> [15:29:06.968] Postcondition failed for step UpdateDefaultRWConcern because [‘currentState.Fickle.DefaultRWConcernCorrect’ = false]. Outcome=3

appreciate advise