When open a query in Microsoft project, the start date changes. Please note that, the start date is a custom field.
I found the answer, update the mappingfile of your project to map the custom tfs field to Project's start field like :
the mapping file can be upload, downloaded using "TFSfieldmapping" command on vs command prompt.
I am still facing a problem, that is when the task has child items, the start date is not reflected. Only for a task that has no child items, the date is reflected properly.