Expected CouchbaseException but got some other exception

collection_command {

  collection {

    bucket_name: "default"

    scope_name: "_default"

    collection_name: "_default"

  }

  unlock {

    location {

      specific {

        collection {

          bucket_name: "default"

          scope_name: "_default"

          collection_name: "_default"

        }

        id: "65a689c7-d862-4feb-a7d8-0a3dc7af0ec8"

      }

    }

    cas: 1710109514166108160

  }

} 

exception {

  other {

    name: "Error"

    serialized: "{}"

  }

}