At my job, we have an error code that is similar to this. On the frontend, it's just like error 123.
But in our internal error logs, it's because the user submitted their credit card, didnt fully confirm, press back, removed all the items out of their cart, removed their credit card, then found their way back to the submit button through the browser history and attempted to submit without a card or a cart. Nothing would submit and no error was shown, but it was UI error.
It's super convoluted. And we absolutely wanted to shoot the tester who gave us this use case.
It's likely a difference of emotion compared to logic. Emotionally they'd think "Damn it, now we need to check for such a weird specific edge-case, this is so annoying" while logically knowing it's better the tester caught it.
Finding stupid ways to break shit, Being able to accurately explain how you broke shit, and being likeable enough that breaking their shit doesn't make the devs angry.