Also, not only did they set up something specifically to capture the emails that they knew weren't intended for them (incidentally preventing the senders' own SMTP servers from alerting the senders of the problem almost immediately), but... it sounds like they also examined the content of some of the diverted emails that they knew were sensitive and not intended for them.
I can't tell from the article whether they've finally disabled this diversion of the emails. Nor whether they had a plan to scrub all copies of the emails before it's out of their control, maybe offering US diplomats/officials a deadline to get a copy if they want it
Also, if they're now acting in good faith, and interfacing with US officials, I wonder who leaked this situation to the press, and why.