What if I get a 2nd, duplicate, Friend Request on Facebook.

There is a very good chance that multiple Facebook requests, from someone who is already in your Facebook friend list, is a fake.

Has their Facebook account been hacked?

Probably not, because if they had hacked the Facebook login, they would not need to send new friend requests.

They are searching for contacts from whom they can extract data.

One tactic is to copy some data, contacts and photos from your page, set up a new one and try to get those people to join their new "fake" page. They then try to gather personal details from your friends, often with uncharacteristic conversational styles in their personal messages.

Check your Facebook Security!

Refer to What's Facebook Security Checkup and how do I start it? | Facebook Help Centre

Action point suggestions!

I would suggest you

1. Ignore the friend request
2. Contact and/or send a screen shot to your friend via their original profile, and suggest they warn their other friends/contacts on Facebook, that this latest request is a fake/scam.
3. If it wasn't them that sent the new one, delete this latest request.

Some people DO lose their password etc and end up creating a second profile, but it is best to make sure.

Tell me more.... Why do Scammers do this?

This link might explain it more and provide you with what to do.

https://www.ricksdailytips.com/beware-duplicate-friend-requests/