I do know that customs compliance is different than typical UPS workflows. I worked on outgoing customs compliance for a while, many years ago. We were the only department in the company who were allowed to change the customer's documentation to be sure that it matched what was in the boxes, and were allowed to open boxes to see what was in them in order to do so. For most UPS employees, that would be an immediate termination, but for us it was literally our job. We tried to minimize doing that, but the entire point was to pro-actively avoid situations exactly as described in the article.
We also had to be somewhat up to date on what was/not allowed to each country, so we could stop shipments doomed to fail before they left the USA. I have no idea if they aren't doing that work anymore in other countries, or if the regulations are just changing so fast that people can't keep up. My guess is the latter.