Dgraph data currupted after Alpha restart

Alpha service crashed during write process. After restart we are getting below error
message": “: cannot retrieve postings from list with key 0: readTs: 1539081 less than minTs: 3702387 for key:”",
“extensions”: {
“code”: “ErrorInvalidRequest”

Are you using the same zero instance used before? I have seen a similar error in contexts where the user cleaned the files in the ZW folder that belong to the Zero instance.