But nobody says potahto, Missouri update

In the 2018 Oscar nominations, the presenter (an African-American woman) used the schwa ending (often transcribed as "-uh" by the IPA-challenged). My ears pricked up, because ever since a Letter From America I heard about 30 years ago I had believed Alastair Cooke's shibboleth,

<autobiographical_note>
He said that both were right in different contexts, The state was one (either /ɪ/ or /ə/ in the last syllable) and the river was the other (either /ə/ or /ɪ/). I thought the nominations would clear this up.
</autobiographical_note>

As a 2012 article in the New York Times says:

In 1907, a resolution introduced in the state House to establish the “only true pronunciation as that received by the native Indians” — a third way, Mih-SOO-rih — failed by voice vote[:]

1907 NYT report of failed vote

<hang_on_though>
"S" in the two syllables in which it occurs"...? Two syllables? Did the word syllable mean something different in the American English  of  1907? [Aha, maybe it‘s a matter of syllabification: "Mis/sou/ri". Anyway....]
</hang_on_though>

But my choice of the word shibboleth was intentional. As the Collins Dictionary says

The original shibboleth was a test word, used for separating Them (the chaff) from Us (the wheat). That Gileadite name for wheat was a pre-Christian version of Beg pardon, I'm soiling the doilies. But in this case there is no Them and no Us. Judging from the many discussions found by Google (more than 2 million – I haven't checked every one, but I think I've got the gist), the difference is mainly geographic. As that NYT article says,

Some believe it started as an east-west split, with St. Louis favoring “ee” and Kansas City “uh.” Popular belief holds that the southern half of the state is “Missourah,” with Highway 70 serving as a sort of Mason-Dixon line, and still others contend that “Missouree” is city, “Missouruh” is country.

Given this geographic/cultural split, there's a tendency for one speaker (often in a single speech event) to use both. And, given this alternation, there's a tendency for the chatterati to try to justify both on esoteric grounds of usage (as Alastair Cooke did – angels and pinheads spring to mind).

But next time that nominations presenter spoke, she flipped and used /ɪ/ or maybe even /i:/. Before the change there was some off-mic hilarity between her and her (Caucasian) fellow-presenter. Perhaps, as the schwa pronunciation had been favoured by President Obama, she had decided to use the version preferred by the wh.... no, that doesn't work. Many white folks unashamedly (indeed proudly) use the schwa pronunciation. I suspect that in Trump's America the down-home version is going to enjoy a renaissance. Anyway, having flipped; she reverted to the schwa.

Anyway, I am none the wiser about this pronunciation. The conclusion seems to be Different strokes for different folks, [and quite often for the SAME folks too].

b

PS A couple more clues:

• Uncle Boris turning somersaults to make TV mogul. (10)
  
• In a way, kudos to University Challenge. (6)