Nav27
There is no way to natively fix that. Our system uses heavy HTML parsing, sanitization, and balancing on incoming rich-text mail. This means anything between <> (like addresses in mail headers) is seen as an HTML tag. Since it is not valid nor can be balanced the system strips the characters themselves and the content between them.
You can customize the code however you will do so at your own risk. I wouldn't recommend it as you could open yourself up to a variety of vulnerabilities and attacks.
Cheers.
