Good catch. I saw an interview with her earlier today with CBS anchor Pat Harvey. I can’t seem to find the video now but in it she said the right side of her face and her right hand went numb shortly after that.
OK, so it’s clear that you think it was a TIA. Branson’s neurosurgeon saying otherwise does not convince you, because he would lie about it if she asked him to. In fact, we never saw him examine her, so she might just have slipped him some cash or a BJ to make this totally bogus statement on her behalf.
I disagree with your interpretation. Her symptoms were consistent with a TIA, a stroke, a seizure, a complex migraine aura, and other less common things. Given her age and sex, the odds of all of these are not equal. Seizure and migraine are more likely than the others. Given her subsequent recovery and statements by her physician, there is no convincing reason to suspect anything other than complex migraine. If you doubt that a migraine aura can cause that particular cluster of symptoms, I can only assure you that in both my professional experience as a physician and personal experience as a migraine patient, they can and do. And I already posted that link on the 15th.
I’ve had the same experience about a dozen times over the past 10 years. Two doctors and a neurologist have told me that the garbled speech is being caused by a headacheless migraine. They all assured me it was not a TIA. Losing my speech capabilities like that was terrifying and disturbing, especially the first time. 
A friend of mine from work called it as a migraine. She said that she’d had a couple of migraines in her life where she had brief episodes where she was completely unsure if what she was trying to say was actually what was coming out.