The same is happening to me. Everything blocked except english, latin1,
latin3 and Western Europe.
On the header of the messages the encoding is:
Content-Type: text/plain; charset="koi8-r"
Looking at
http://en.wikipedia.org/wiki/KOI8-R
It appears that to sucessfully block Russian messages we need to block
KOI8-R, KOI8-U, KOI7, ISO8859-5 and WINDOWS-1251.
When we block the encoding for Cyrilic we are probably not blocking
everything we need.
Anyone knows how to fix this?