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 the symbols (3 red 7's) 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).

Edit: I also have to mention that slot machines are made by only a handful of companies, and are regulated. They are bought by other companies (casinos) that are also regulated. Asking a casino to modify the software on a slot machine would be akin to asking them to fly to the moon. They don't know how to do it, and they make money without modifying the software anyway. My example with the progressive amount: older machines have a true/false setting for progressive jackpots, leaving it up to human error.

My job is to literally pay jackpots, I do it several times a night.

We’ve never had a glitch like this where I work, and if we did we’d fucking meme on it forever lmao

You could be right, but I think it's a 32-unsigned for three reasons:

1. Slot machines have no need to handle fractions of pennies.

2. Slot machines operate with "credits" as it's base unit. 1 credit is the smallest unit. This is most likely a penny slot, so 1 credit = 0.01, and the most it can probably store in memory is probably 4,294,967,295 credits, which is very nearly $43 million (suspiciously the same as the erroneous amount on the screen). Older dollar machines have $1 = 1 credit, and can't handle pennies at all, and will reject tickets less than a dollar. If you give these older machines, say, $1.69, it will hold $1 as credit and print a ticket for $0.69 because it has no way of handling it.

3. Diagnostic software handles "credits" as an integer. Coin in, coin out, current credits are all whole numbers. When using the software to inspect a machine, you have to know the denomination of the machine to know how much money is on it (denom times credits = amount).

This machine looks old as hell from the image in the article. I'm not familiar with this style, though, we don't have these where I work.

And you're right, this is certainly more than the "maximum payout" reported by the makers of the slot machine. The innards of a slot machine aren't very mysterious from a technical standpoint, they can only produce a finite set of payouts, this isn't one of them. There isn't a sort of hard-and-fast stop for how much a machine can pay, more like it can only algorithmically produce a finite set of payouts.