The divorce papers state that Ann and Obama were lawfully married on 2/2/61 and were man and wife until the divorce proceedings. The divorce papers also say they had one issue, Barack Obama II.
It doesn’t matter what the divorce papers say. They can put anything they want in there. This family was a bunch of liars.
There was no lawful marriage on that date. There may have been a marriage but it wasn’t a lawful one. Obama certainly knew he was already legally married. Ann may not have known.