TN erratic behaviour in recognizing content

my java client does http post of xml document to a wm IS service, this service then does routeXML.
In my ten iterations of doin this, two times the content is not recognized in TN and it is stored as bytes of type “application/x-wmidatabin” in TN. Rest of the times, it is recognized as xml content and i see that xml in TN.
For all the 10 iterations, i am reading the same xml file and posting it to TN, with Content-Type set to text/xml
I noticed this behaviour when i submitted the same xml doc to TN thru browser.

Any help is higly appreciated