But there is/was a residency stipulation and his mother didn’t meet the qualification because she wasn’t old enough (5 years after 14th birthday and she was only 4 or less years after her 14th birthday).
Yes, Dunham wouldn’t have met the residency requirement to pass on her U.S. citizenship to a foreign-born son with a noncitizen father; I explain that in detail in my post #168.
My post #432 was about a separate clause and a separate theory that Obama might use to claim citizenship if he was born abroad—that his parents weren’t really married, so he was born out of wedlock to a mother with U.S. nationality who previously had lived at least one uninterrupted year in the U.S. As I said in my post (and a follow-up), I’m not sure if his mother could have passed on her citizenship or merely her nationality, which are two separate things.