Error "Missmatch cas values" when using EXECUTE __update

// BEGIN WORK

QueryResult beginWork = cluster.query("BEGIN WORK");

String txId = beginWork.rowsAsObject().get(0).getString("txid");

// EXECUTE __get and retrieve scas

QueryResult get = cluster.query("EXECUTE __get",

QueryOptions.queryOptions()

        .raw("txid", txId)

        .parameters(JsonArray.create()

                .add(keyspace)

                .add(docId)));

JsonObject row = get.rowsAsObject().get(0);

String scas = row.getString("scas");

// scas is "1604402229268185088"

// Generate txdata of 

// {"cas":"1604402229268185088","kv":true}

JsonObject txdata = makeTxData(Optional.of(scas), txId);

// EXECUTE __update sending back that scas

QueryResult replace = cluster.query("EXECUTE __update",

        QueryOptions.queryOptions()

                .raw("txid", txId)

                .raw("txdata", txdata)

                .parameters(JsonArray.create()

                        .add(keyspace)

                        .add(docId)

                        .add(updated)

                        .add(JsonObject.create())));

{"code":17099,"message":"UPDATE - cause: Missmatch cas values(0,1604402229268185088) for key d29cdea4-fec7-46a3-9e5c-455c5e967fac"}