Snapshot deletion fails with remote_transport_exception and number_format_exception

Hey,
Upon deleting a snapshot (stored in S3) using the DELETE API we get the following error:

{
"error": {
"root_cause": [
    {
        "type": "remote_transport_exception",
        "reason": "[PROD-master-elastic1][xx.xx.xx.xx:9300][cluster:admin/snapshot/delete]"
    }
],
"type": "number_format_exception",
"reason":"For input string: \"2\""
},
"status": 400
} 

There are no additional logs that seem relevant.
Elasticsearch 5.6.9

Any ideas?

Welcome!

Could you share what exact query you sent to the cluster?

Thanks,

DELETE on http://elasticsearch1:9200/_snapshot/snap-repo/snap-name