I have been lurking on the forums, but have yet to come a situation like mine.
I used to be an AU on my dad's Amex. I had it for 9 months, but then we got into an argument unrelated to the Amex account. He decided to show me who's boss and closed my AU account on his Amex.
However, here's the strange part. The closed AU account still reports as a trade line. My total credit utilization still takes in the closed AU's credit limit. And the strangest of all is that it's still gaining history!
I used to pay for the Amex since my dad hardly uses it so I have the login and password. I checked and saw that my AU account had disappeared. So that confirms that he did close my AU account. The Amex is still active.
It was closed on August 2012. That made it 9 months from the month it was opened.(October 2011) On my credit report, it reports 1 year and 4 months.