It seems to me (somebody who has no chops in this domain) that this is such a basic bug. Like something a child would have found just messing around.
And it came from a corporation that has around $200B of cash and cash equivalents. Apple has the resources to test and find bugs like this.
That Apple didn't find it is down to leadership and priorities more than some inherent limits of producing reliable code. One spends on what one thinks important.
But who knows, I've got no domain expertise here. Maybe a fifth of a trillion dollars C&CE really isn't enough to fund production of more robust code. But really?
