Problematic email delivery in China?

China's internet censor system has been messing around with email messages coming into the country, says Danny Levinson of BDL Media and an article at Reuters.

In layman's terms, the problem seems to be that often, but not always (and unfortunately not always easy to replicate), emailing into China from outside servers get bounced, and sending from inside China out also sometimes, but not always bounce. Sure, this happens in general, sometimes. But since about 2AM on Monday morning, it's been quite problematic.

I have been writing before about the new nanny-software China seems to be testing, but had not noted any problems with the email delivery. What is annoying is the unpredictable way it switches off my Google news searches, but I just restarted my proxy and that problem is now gone.
It is clear that we can throw our old ideas about how the Great Firewall of China's internet censors works in the dustbin. Like the introduction of previous systems, new systems cause a massive amount of problems and the only positive side of it is that in those precious months you can actually learn how the system works.