GST registration

What is the need to apply again with same details? Even u apply for the third time they will ask for same clarification again unless & until u donot incorporate the clarification sought in fresh application. So it's better to give reply to the clarification sought for if time period for reply is not lapsed.

At first time of registration time limit for giving classification was expired
at second time there was some mistake at the time of registration which the party realised just after submission.
so he again applied registration for 3rd time on the same day.

It means u have applied for registrartion two time on same day with same PAN Number. In such case P.O. will get confuse regarding which application should be scrutinized. In case of mistake u should apply again after expiry of period of clarification. Now as per me U should meet with your concerned P.O. & give an application to scrutinize latest application filed.

I have made aadhar Authentication of the latest application and got GSTIN and leave the earlier application as it is without aadhar Authentication.

Okae in this case ur 3rd application will be scrutinized first as P.O. is required to take any action(either grant application or issue clarification) within 3 days of submission of application as u have done adhar authentication.

After issue of GSTIN ur 2nd application will automatically get rejected bcz of already GSTIN issued.

So sit & relax. Wait for action by P.O.