Missing Characters in ending tag in XML

I am generating a XML in asp.net ,XML is generated something like this

<?xml version="1.0" encoding="iso-8859-1"?>
<XMLFiling xmlns:xsi="http://ift.tt/ra1lAU"     xmlns:xsd="http://ift.tt/tphNwY">

.........


 </XMLFilin

Last two characters are missing?What can be possible reason for this

P.s.- Code is too large to post,also debugged the whole code and didn't find any issue with length of file