Dear Friend
Generally, when we asked the previous employer about the credentials of his ex-employee, he may say like that as you are quoting now. First of all we have to see, whether the date of joining and date of relieving, salary drawn by ex- employee during his tenure with his previous employer are found correct or not in a reference with his ex-employer, we need not worry about other petty reasons. Why because, in the interview itself, you have accessed his skill and suitability for the job and finally you are making reference to know about the selected employee.
Except professionally managed companies in India, traditional management firms may not give correct reference with regard to its ex-employees for one or the other reason. So hundred percent we could not relied upon the reference of ex-employers with regard to their ex-employees whom we have selected to meet our requirement
Regards