We encounter an undesired behaviour of the SMT given the following input documents (other props removed for brevity):

MongoDB original document:

{
    "_id" : ObjectId("61af15fcac9f5896f6c2d03f"),
    "id" : "CRSRF-a610fbe0-be92-4dbf-b333-e2c76f71f361"
    "vendor_id": "a610fbe0-be92-4dbf-b333-e2c76f71f361",
}

Document in Kafka topic:

{
  "id": "61af15fcac9f5896f6c2d03f",
  "vendor_id": "a610fbe0-be92-4dbf-b333-e2c76f71f361",
}

Please note, that the SMT decides to overwrite the `id` property in the resulting document due to here and here.

Although the schema of the document is not well designed, I would argue, that DBZ should not overwrite document properties by default. I would either assume that this is configurable (e.g. write _id in to doc as "foo") or at least should be behind a toggle.

jpechane and I had a conversation about this here and we agreed that I hand in a patch that makes the behaviour configurable, keeping the current behaviour as its default for backwards compatibility.