So, what I understand is that somehow it got reported on your 2015 return....which has already been filed. That means you did claim the income already. I have run into these kind of situations a number of times before (where the refund is received TWO years past its tax year) and IRS only cares that the income is claimed. It went into your 2015 return and trust me....they can and do see that. I didn't tell you to file an amended 2015 return simply because, in my opinion, it is not necessary but it is totally up to you. Best of luck!
