You may find in some situations, the Symantec Messaging Gateway(SMG) could not filter messages by using custom Content Filter(CF) policies as expected.
The conditions in these CF policies may just defined to filter some key words or regular expressions to check the message headers/bodies, and it works in most cases, but it doesn't work when the subject is too long or it contain to many DBCS (double-byte character set).
There is a issue when processing 'encoded-word', which were follow RFC2047.
Symantec has acknowledged this issue and working for the solution.
Affected SMG versions: 9.5.x, 10.0.0-x and 10.0.1-2.