JSON Schema verification - null value exceptions on non-required properties

[d4rkm4tterz]

I'm having a weird problem when using the 10.6.x S3 connector (and also 10.5.7) with a JSON schema - whenever I add a non-required property I keep getting a "org.apache.kafka.connect.errors.DataException: Conversion error: null value for field that is required and has no default value" error when records are consumed by the connector.
So for example, using the following schema:

{
  "type":"object",
  "properties": {
    "customer_id" : {
      "type": "string",
      "default": ""
    },
    "correlation_id": {
      "type": "string"
    },
    "sku": {
      "type": "string"
    },
    "strategy": {
      "type": "integer"
    },
    "billing": {
      "type": "boolean"
    }
  },
  "additionalProperties": true
}

and this example event:

{
  "api_client_id": "",
  "auth_type": "",
  "billing": true,
  "correlation_id": "4f0144c2-5bd8-4ce2-b2c1-f18bfe674102",
  "country": "",
  "device_type": "",
  "erid": "",
  "event": "verify",
  "event_date": 0,
  "event_type": "not_applicable",
  "kyc": false,
  "msisdn": "",
  "pgcid": "998c1e0-173b-4a16-bcfb-182cc48fbb93-1737573592407",
  "sku": "sample_sku",
  "strategy": 1,
  "ts": 1745495247914
}

will result in the 'Conversion error' although the schema passes verification using 3rd party tools.

When I remove the customer_id prop from the schema, it works and the resulting event in S3 has only the props defined by the schema.

What's causing this behavior? Any suggestions welcome.