Navneet,
I think the file coming to PI Qual is having some encoding issue.
You said, "there is no difference between PI Dev and PI Qual".
Please point PI Dev (sender channel) to Quality source folder and test the interface. Let us know the result. If you copy file from Quality source folder to Dev source folder, encoding may get corrected and you will not able to debug.
Also compare hex values of Dev and Qual file. Notepad++HEXeditor - YouTube