Everyone knows that. It was in the news in January 2013 I think.
This is both true AND false at the same time. During the ratification process of the 13th Amendment, Mississippi was a holdout as they appealed the decision to not compensate people for the loss of their slaves. The Amendment was obviously ratified and placed into the Bill of Rights making it so no laws could be created to undermine it. Due to so much change occurring which required congressional oversight, Mississippi forgot to sign the forms and get them mailed in. Two people found the oversight a few years ago and Mississippi signed the papers then sent them in. ***Note: States only have a limited time to send in the paperwork so technically they still have not agreed to the Ratification as the time limit has expired.*** So yes they symbolically signed it recently, however, they are still documented as a party voting "Nay" for the ratification of proposed Amendment 13.
what on earth?
I do not think that's true.
I don't know if that's true, if so, it both doesn't surprise me and probably just means that they hadn't ratified the 13th Amendment. But I don't know