The fileExist=Append option on the Camel File component not working in Fuse

Issue

• Create below route which should append the content of all the files of inbox to test_output.txt but It's overriding the file with the content of last file present in inbox

<route id="fileAppend">
   <from uri="file:/path/inbox" />
   <setHeader headerName="Exchange.FILE_NAME" id="_setHeader1">
      <constant>test_output.txt</constant>
   </setHeader>
    <to uri="file:/path/outbox?fileExist=Append" />
</route>