I wasn't specific, because I'd rather not piss of my employer. But anyone who works in a similar space will recognise the pattern.

It's not underspecified. More... Overspecified. Because it needs to be. But AI will assume that "impossible" things never happen, and choose a happy path guaranteed to result in failure.

You have to build for bad data. Comes with any business of age. Comes with international transactions. Comes with human mistakes that just build up over the decades.

The apparent current state of a thing, is not representative of its history, and what it may or may not contain. And so you have nonsensical rules, that are aimed at catching the bad data, so you have a chance to transform it into good data when it gets used, without needing to mine the entire petabytes of historical data you have sitting around in advance.