I've got a hosted exchange solution through Apptix, which isn't the problem, I think, but it may be relevant.
I have my main account, firstname.lastname@example.org, and to that, I have an alias, email@example.com.
Whenever I send an email to firstname.lastname@example.org, I examine the headers, and I see the "To:" field being correct, "To: email@example.com". All is well.
I recently set up another user, firstname.lastname@example.org to function as a multipurpose mailbox. I aliased "email@example.com" to the services account in the same method that I did "firstname.lastname@example.org", however nothing I have sent to "email@example.com" actually goes TO "firstname.lastname@example.org". All of the headers say "To: email@example.com". This makes it extremely difficult to filter based on headers alone.
Does anyone have any feedback on what settings I would need to look at in order to fix that?