I have a javascript snippet written which checks for the mime type of the files.
var type = this.files[0].type;
Code was running fine for a long
Finally, i got the answer for my question and here is reason why this was happening on some machines.
As i was expecting, issue is system specific where content-type for .csv type is missing under Registry (HKEY_CLASSES_ROOT.csv).
See screenshot, This entry was missing on some machines.