SAP Digital Manufacturing Cloud.
I have this simple router defined:

I have an SFC in Queue at the ASSEMBLY Operation (Activity ID 20), and am trying to use a Production Process that calls the Change Production activity to move the SFC to Activity ID 10. When I debug the process, I get a response that says failed for the SFC. Here is the response detail:
- [Info]Indication Color 5 Started process instance with id 36124ace-2f04-45cc-acf5-fe3b93c141cc
- [Debug] Variable STEP_ID is created with value: 10
- [Debug] Variable ROUTER is created with value: KGB_PRO
- [Debug] Variable ROUTER_VER is created with value: A
- [Debug] Variable SFC is created with value: KBG01001
- [Debug] Variable OPERATION is created with value: WELDING
- [Info]Indication Color 5 In StartEvent, executing NoneStartEventActivityBehavior
- [Info]Indication Color 5 Sequence flow will be taken for 696d95b0-1b82-425f-b6a3-9cc1f5d13977 --> 28cc53a9-10cf-43af-8b7f-a736c89e21d5
- [Info]Indication Color 5 In ScriptTask, executing SecureJavascriptTaskActivityBehavior
- [Debug] Variable RouterType is created with value: PRODUCTION
- [Debug] Variable SFC is updated with value: KBG01001
- [Debug] Variable ROUTER is updated with value: KGB_PRO
- [Debug] Variable OPERATION is updated with value: WELDING
- [Debug] Variable RESOURCE is created with value: null
- [Debug] Variable STEP_ID is updated with value: 10
- [Debug] Variable ROUTER_VER is updated with value: A
- [Info]Indication Color 5 Sequence flow will be taken for 7c182373-e5ef-48a0-be8b-ad41de67b156, 28cc53a9-10cf-43af-8b7f-a736c89e21d5 --> eb82c64c-62b3-46f1-ab28-e4808b745f22
- [Debug] Variable Change_Production__plant is created with value: ELS01
- [Debug] Variable Change_Production__sfcs is created with value: ["KBG01001"]
- [Debug] Variable Change_Production__routingStepId is created with value: 10
- [Debug] Variable Change_Production__bom is created with value: null
- [Debug] Variable Change_Production__resource is created with value: null
- [Debug] Variable Change_Production__operatorID is created with value: WELDING
- [Debug] Variable Change_Production__routing is created with value: {"routing":"KGB_PRO","routingType":"PRODUCTION","version":"A"}
- [Info]Indication Color 5 In HttpServiceTask, executing ClassDelegate
- [Debug] Service Change_Production starts to execute with method: POST
- [Debug] Service Change_Production starts to execute with url: /api/v1/changeProduction
- [Debug] Service Change_Production starts to execute with body: {"plant":"ELS01","sfcs":["KBG01001"],"routingStepId":"10","resource":null,"operatorID":"WELDING","routing":{"routing":"KGB_PRO","routingType":"PRODUCTION","version":"A"}}
- [Debug] Variable Change_ProductionResponseProtocol is created with value: null
- [Debug] Variable Change_ProductionResponseStatusCode is created with value: 200
- [Debug] Variable Change_ProductionResponseReason is created with value: OK
- [Debug] Variable Change_ProductionResponseHeaders is created with value: cache-control: no-cache, no-store, max-age=0, must-revalidate content-security-policy: script-src 'self' content-type: application/json date: Thu, 17 Aug 2023 12:34:42 GMT expires: 0 pragma: no-cache server: nginx vary: accept-encoding x-content-type-options: nosniff x-correlationid: 3b044e75-b231-47f1-4548-5b6f05272d72 x-frame-options: DENY x-vcap-request-id: 7f339237-7718-4c52-6859-7ab30dc8c463 x-xss-protection: 1; mode=block transfer-encoding: chunked strict-transport-security: max-age=31536000; includeSubDomains; preload;
- [Debug] Variable Change_ProductionResponseBody is created with value: {"success":[],"failed":["KBG01001"]}
- [Info]Indication Color 5 Sequence flow will be taken for eb82c64c-62b3-46f1-ab28-e4808b745f22 --> cda78db3-12ad-4387-b252-f75a79d9ea21
- [Info]Indication Color 5 In ScriptTask, executing SecureJavascriptTaskActivityBehavior
- [Debug] Variable Change_Production__success is created with value: []
- [Debug] Variable Change_Production__failed is created with value: ["KBG01001"]
- [Info]Indication Color 5 Sequence flow will be taken for d29156a6-fd47-475f-8bde-07f84bff249d, cda78db3-12ad-4387-b252-f75a79d9ea21 --> dff8a915-6cd1-4d2c-ad0f-4ea52a13d1b2
- [Info]Indication Color 5 In ScriptTask, executing SecureJavascriptTaskActivityBehavior
- [Info]Indication Color 5 Sequence flow will be taken for dff8a915-6cd1-4d2c-ad0f-4ea52a13d1b2 --> 853a5653-c14d-4b7f-9ca1-54067f83d6a1
- [Info]Indication Color 5 In EndEvent, executing NoneEndEventActivityBehavior
- [Info]Indication Color 5 Completed process instance with id 36124ace-2f04-45cc-acf5-fe3b93c141cc
Any ideas as to why this call fails as shown?