Well here's some wild and crazy conjecture intertwined around some known truths:
Maybe when Stanley Anne came home to Mom & Dad from Mombasa, baby in tow, they refused to take her in. In 1961 it was beyond embarrasing for a family to have a daughter get pregnant out of wedlock (no marriage certificate found yet, right?). So, for a few days, (August 9th - 11th?) she stayed with some of Dad's friends, and registered the birth in Hawaii at that time. But it wasn't working out, so she split for Washington State. Then, by August 14th, she registered his birth in Vancouver, since Hawaii probably didn't register him as a US citizen, and the Canadian option was the next best thing in Stanley Anne's mind.
BHOsr. may have stayed in Kenya this whole time, or is that known to be otherwise?
Obama Sr. started at Harvard in the fall of 1961.