it better be well-established that cherry-coin-grape is the deciding output and not the display.

Yes, this is how it works. This is the regulated language. All symbols have pays associated with them.

I will give you another example: You hit red seven, red seven, red seven on a progressive machine. The progressive displays a value of $1,079 (and does not reset after the win) but the machine only pays $1,000. This is a problem with the settings of the machine, and the casino is required to pay the progressive amount of $1079 and possibly be fined for having a misconfigured machine. This is because the pay table lists this as awarding the progressive prize. Pay table is law.

I also suspect that the machine did not display a win of $43 million at all. I suspect the glitch occurred either when the win was added to her credits or when the ticket was printed (an error in memory, not in game logic).