I got a 1099-g for a tax credit we recieved in 2013 from Arizona. We haven't lived there for three years. Why did this happen? Do I need to report it?

When did you receive the refund?

If the form was received in 2017 for a 2013 refund, you should report it on your 2016 tax return. I've heard of similar cases, but it is odd.

I received the refund in 2013 but the form again this year. I've already received a form for this money in previous years and reported it. Why did I get another one?

Weird. Some glitch in their computer system. If you've already reported this income, then ignore the most recent form. But keep all your records, in case the IRS decides to contact you.