OS Connector not sending messages to Dead letter Queue topic

Hello,

we have Opensearch connector configured to send data to OS. However the records that are failing the due to serialization error is simply getting dropped and lost instead of sending them to DLQ topic.
Can someone please help us figure out what could be the probable cause or even if avien support DLQ ?

Please find the connector config below

{
"connector.class": "io.aiven.kafka.connect.opensearch.OpensearchSinkConnector",
"type.name": "_doc",
"behavior.on.null.values": "ignore",
"auto.create.indices.at.start": "false",
"tasks.max": "150",
"connection.timeout.ms": "3000000",
"drop.invalid.message": "false",
"max.retries": "5",
"key.ignore": "true",
"retry.backoff.ms": "30000",
"errors.deadletterqueue.context.headers.enable": "true",
"errors.deadletterqueue.topic.replication.factor": "3",
"read.timeout.ms": "300000",
"topics": "b6vv_onevz_nsacxp_payload_log-grp1",
"batch.size": "300",
"max.in.flight.requests": "4",
"schema.ignore": "true",
"behavior.on.malformed.documents": "REPORT",
"flush.timeout.ms": "300000",
"max.buffered.events": "300",
"errors.deadletterqueue.topic.name": "dlq_b6vv_payload_log-grp1_test",
"name": "eks-flb-msk-os-b6vv-onevz-nsacxp-payload-log-grp1-2-conn-sink",
"errors.tolerance": "all",
"connection.url": "https://vpc-vz-b6vv-nextgen-li6-7omprnsqqujw7ndad5yufgox7a.us-east-1.es.amazonaws.com",
"linger.ms": "3000"
}

Thanks