mis delivered mail (but only spam is misdelivered)

[linuxcat]

I expect the problem is invalid headers but I have noticed a pattern to the misdelivered mail. Correctly delivered mail comes in the form of either:
John Doe <jdoe@example.tld>
OR
jdoe@example.tld

All of the spam that is getting delivered to the wrong recipients comes in the form of:
<jdoe@example.tld>
It has the <> but no real name in front. It may be something completely different, but all of the problem mail is in this form.

Is there something I can do about this? Do I need new lines in my virtusertable?
I have
jack@example.tld jack
michelle@example.tld michelle
If I added:
<jack@example.tld> jack
<michelle@example.tld> michelle
would that fix it?

I am not really wanting to work that hard at getting spam delivered correctly but my users think it is really odd that they are receiving mail with someone else's address in the to.


Jack