Every time I try to add a service line to a repair order I get this error. This happens even if I pass in the right etag header and make a fresh get repair order call right before adding the service line.  Request 1:  GetRepairOrder:  {"type":"cdk_api_call","timestamp":"2026-02-26T07:33:11.674Z","operation":"getRepairOrderById","endpoint":"/service/cdk-drive/v2/repair-orders/159928","method":"GET","duration":1267,"requestId":"cdk_1772091191674_mfie83c","requestHeaders":{"Subscription-Id":"62e95d5a-2185-4cd1-a336-ef1176c91db0","Request-Id":"27bc296a-ef2f-4ec7-bf58-0d81fe1f4620","Accept":"application/json","Cache-Control":"no-cache","Pragma":"no-cache","Authorization":"Bearer eyJ...9YUg","Content-Type":"application/json"},"responseStatus":200,"responseBody":{"repairOrderId":"159928","blockIvrFlag":false,"comments":"","customerHref":"https://api.fortellis.io/cdkdrive/crm/v1/customers/1384879","customerContactInfo":"3110235355","vehi...{"value":54712,"units":"MI"},"status":{"code":"I91","description":"OPENED"},"dispatchMakeCode":"C","transportType":"WAITER","dropOff":{"dateTime":"","address":"","city":"","note":"","phone":"","vanNumber":""},"pickUp":{"dateTime":"","address":"","city":"","note":"","phone":"","vanNumber":""},"poNumber":"","serviceAdvisorId":"997317","remarks":"","tagNum":"7362","serviceLineItems":[{"serviceLineId":"A","serviceRequest":"Balance tires","cause":"","comebackFlag":false,"jobStarted":false,"dispatchCode":"S10","estimatedDuration":0.6,"laborType":"C","technicianId":"","laborEstimate":0,"lubeEstimate":0,"miscEstimate":0,"partsEstimate":0,"serviceEstimate":0,"subletEstimate":0,"taxEstimate":0,"laborOperations":[{"laborOperationId":"1","forceShopChargeFlag":false,"laborType":"C","opCode":"B2831","opCodeDesc":"Balance tires","soldHours":0.6,"saleAmount":57.95,"saleOverrideFlag":false,"shopCharge":0}],"status":{"code":"I91","description":"OPENED"}}],"estimate":{"authorized":0,"labor":0,"parts":0,"misc":0,"lube":0,"sublet":0,"tax":0},"promiseDateTime":"2026-02-25T08:15:00","links":{"self":{"href":"https://api.fortellis.io/cdkdrive/service/v2/repair-orders/159928"}}},"responseBodyCount":1} [getRepairOrderById] Response ETag: "9268422" Request 2:  Add Service Line:  {"type":"cdk_api_call","timestamp":"2026-02-26T07:33:12.360Z","operation":"addServiceLine","endpoint":"/service/cdk-drive/v2/repair-orders/159928/service-lines","method":"POST","duration":682,"requestId":"cdk_1772091192360_k55o0rz","requestHeaders":{"Subscription-Id":"62e95d5a-2185-4cd1-a336-ef1176c91db0","Request-Id":"0d6d6241-8ee6-4f37-a016-03303f7a1bb3","If-Match":"\"9268422\"","Content-Type":"application/json","Accept":"application/json","Authorization":"Bearer eyJ...9YUg"},"requestBody":{"serviceLineItem":{"serviceRequest":"Front Wiper Blades","comebackFlag":false,"estimatedDuration":2,"laborType":"C","laborEstimate":20,"partsEstimate":468,"miscEstimate":0,"lubeEstimate":0,"subletEstimate":0,"taxEstimate":0,"serviceEstimate":488,"laborOperations":[{"opCode":"N2609","opCodeDesc":"REAR WINDOW WIPER AND WASHER SWITCH REPLACEMENT","soldHours":2,"saleAmount":0,"saleOverrideFlag":false,"forceShopChargeFlag":false,"laborType":"C","includedParts":[{"partNumber":"234","partNumberDescription":"test","partQty":2,"saleAmount":234,"fixedSaleFlag":false,"includesCoreFlag":false,"mfrCode":"CHEV"}]}]}},"responseStatus":400,"responseBody":[{"message":"A change was made to the repair order: 159928 earlier, verify the changes occured before performing the operation.","code":400}],"responseBodyCount":1,"error":"400 Bad Request"}