LMTP bounces with invalid chars in MAIL FROM adress

[Simon Matter]

Hi,

I've seen a growing number of bounced mails from Cyrus LMTP where Postfix
logs "501 5.5.4 Syntax error in parameters (in reply to MAIL FROM
command))"

The problem is that those messages really have invalid from adresses, like
"RosaSánchez at something.com", but Postfix still accepts them. Later, Cyrus
runs parseaddr() on it ans correctly refuses to accept the mail.

Now, I'm interested to hear how others handle this case, if possible how
they handle it with postfix. I know that enabling strict_rfc821_envelopes
would possibly help but that seem to be a bad idea.

Regards,
Simon