If you are wondering what happens when you duplicate an ad inside an adset multiple times, the answer is the AdId will change, and the social proof will not be shared. That means if your main ad received 10 likes, and 5 comments, and you duplicate the ad, the new duplicate will have 0 likes, and 0 comments and count as a brand new ad in facebook ad system.
IF however, when you create your ad, you set it to use existing post, and duplicate the ad afterwards, it WILL share the engagement/social proof. Don’t know why facebook does this, but you do want the engagement shared for the most part so try and use existing posts.
If you have any questions, be free to ask us on the forum.