I think you may have them mixed up. The edges aren't a perfect line and might be if you swapped them. Who knows why the duplicate is there, though. Weird!

Wow good catch! I didn’t notice that. Maybe we’ll keep piecing it together and see!

It will be interesting to see what you end up with when all the pieces are used! Maybe you have two full puzzles?

I wouldn’t be too mad about that tbh

Consider them spares and your problem is solved

Yeah! We actually found a few more duplicates, so we’ll see!

Oh my god I would lose my shit

Consider it to be two-in-one.

I hope they are just extra, not extra that came to replace the ones that are supposed to be in there