strange cases in content modifier

Dear Expert,

need your help.

i found some strange cases on my IFLOW

at my content modifier 6, i put in this

but i encountered the problem

[CAMEL][IFLOW][EXCEPTION] : org.apache.camel.FailedToCreateRouteException: Failed to create route Process_1 at: >>> Split[bean[ref:splitter method:splitGeneral] -> [SetProperty[effectiveStartDate, xpath{XPath: //effectiveStartDate}], SetProperty[externalCode, xpath{XPath: //externalCode}], SetProperty[transactionSequence, xpath{XPath: //transactionSequence}], SetProperty[cust_Balance, xpath{//cust_Balance}], SetBody[simple{${in.body}}], SetHeader[MessageId, simple{${in.header.SapMessageId}}], To[sap-map-pi:openOrder], To[dataformat:sap-xmljson:marshal?jsonEncoding=&ignoreNamespaces=false&jsonNamespaceSeparator=:&xmlNsToPrefix=#xmlNsToPrefix_CallActivity_29&dropRootElement=true], Multicast[[To[direct://SequenceFlow_196], To[direct://SequenceFlow_198]]], SetHeader[Content-Type, constant{multipart/form-data; boundary=cpi}], SetBody[simple{${in.body}}], To[direct:Process_173], Choice[[When[simple{${property.getData_url} != ''} -> [To[direct:Process_183], SetHeader[scriptFile, constant{script6.groovy}], SetHeader[scriptFileType, constant{groovy}], Bean[ref:scriptprocessor method:process], To[direct:Process_260], SetProperty[SAP_MarkMessageAsFailed, constant{false}]]]] Otherwise[[SetHeader[scriptFile, constant{script8.groovy}], SetHeader[scriptFileType, constant{groovy}], Bean[ref:scriptprocessor method:process], To[direct:Process_260], SetProperty[SAP_MarkMessageAsFailed, constant{false}]]]]]] <<< in route: Route(Process_1)[[From[direct:TransactionWallet_Upgrade2_Tim... because of java.lang.ClassNotFoundException: java.lang.string
  [CAMEL][IFLOW][CAUSE] : Cause: org.apache.camel.RuntimeCamelException: java.lang.ClassNotFoundException: java.lang.string
    [CAMEL][IFLOW][CAUSE] : Cause: java.lang.ClassNotFoundException: java.lang.string

the question is why my property balance was different with each other ?

SetProperty[transactionSequence, xpath{XPath: //transactionSequence}], 

SetProperty[cust_Balance, xpath{//cust_Balance}]

as you can see i dont have XPATH: at my property balance

any idea ?

thank you