Production Issue: ENGINE-16004 Exception while closing command context: null

I have had a process running for well about a year and a half and not one single issue.
Quotes get sent to an EDM and indexed. I pull the indexed values from the EDM and launch a process around it.
Some long forms are captured, etc.

Now for some reason out of the ether this error pops up:

12-Apr-2023 12:13:17.766 SEVERE [http-nio-8080-exec-10] org.camunda.commons.logging.BaseLogger.logError ENGINE-16004 Exception while closing command context: null java.lang.NullPointerException 12-Apr-2023 12:13:17.767 WARNING [http-nio-8080-exec-10] org.camunda.commons.logging.BaseLogger.logWarn ENGINE-REST-HTTP500 java.lang.NullPointerException

Thats it, no additional call stack info.
And my users get presented with the following error in Task Manager:
This happens after submitting an embedded form.
(Note this works for ALL other flows except from this one dealer)

An error happened while submitting the task form:
Unsuccessful HTTP response.

Response HTTP:

    "type": "NullPointerException",
    "message": null

URL: http://[URL REMOVED]:8080/camunda/api/engine/engine/default/task/74c72a34-d91a-11ed-a78a-0242fb12859d/submit-form
Status: 500
Source: Network
Address: [IP REMOVED]:8080

POST BODY: (Information Redacted)
    "variables": {
        "customerApplication": {
            "value": "{}",
            "type": "Object",
            "valueInfo": {
                "objectTypeName": "flow.model.CustomerApplication",
                "serializationDataFormat": "application/json"
        "applicationDocuments": {
            "value": "[]",
            "type": "Object",
            "valueInfo": {
                "objectTypeName": "flow.model.ApplicationDocument>",
                "serializationDataFormat": "application/json"
        "applicationDocumentsAreInOrder": {
            "value": true,
            "type": "Boolean",
            "valueInfo": {}

Basic Auth
Json Serialized Variables

And there is NOTHING in the logs except for that one line.
So I reproduced everything on my dev environment and reproduce the process variables locally so as to have the identical workflow and the form submitted no issues and the process carried on as expected.

I have no idea where to go from here? How does one even begin to diagnose this?
It is clearly state based (Database?), both configs are identical from dev to local.
Same code, same browser.
It is not permissions as I am admin and get a similar result in production.
Any help, please