We had a similar situation in Russia. A mobile operator was cooperating with government to hack into activists' Telegram accounts. They disabled SMS service for a user and then requested a password restore using SMS, intercepted it and got access. But they forgot to delete this information from their internal systems, so when the user called support, they told them that SMS service was disabled, and later even gave a signed confirmation about it.
I don't know whether the story from the article is true or not, but people tend to make such kind of mistakes. Imagine a typical accounting system, written on bunch of legacy technologies during last 20 years, and think how difficult it would be to remove all traces from all the databases and logs and not break anything. And tell every employee that would process the package not to scan it.