Question: With the ability to migrate questions, I have found quite a few duplicates on both SU and MSO due to questions being migrated from others sites.

Do we handle these as normal duplicates or should we just let them be?

Answer: 
This was implemented with the Mortarboard (bronze), Epic (silver), and Legendary (gold) badges!
I don't know if it should apply to *all* votes after the rep cap is reached. Instead, how about a badge for a non-wiki answer with X upvotes that was posted *after* the author reached their daily cap?

As a side note, this happened to me the other day on SuperUser - I was capped out and I posted an answer that rapidly gained 15 votes. I'm glad it was so well received, but I couldn't help but wish that the question (and my answer) were posted when I wasn't already capped out.