This is already unchecked, although this does not appear to be the related setting. It seems like this setting would turn all incoming emails from the configured incoming server into leads. My problem is, OpenERP selectively turns some emails into leads. Its somehow parsing my incoming leads to determine what type of email it is, (whether its a lead, or some other document type), then creating the lead document and adding a message to the lead.

Please see the comment above. That setting is set to blank. Again, its not that all my emails are turning into leads, openerp is somehow parsing my incoming emails to determine what document type it is. Then creating the necessary document. Most emails go straight to my inbox.

Try to see under "Settings ---> Technical ---> Automated Actions ----> Automated Actions" if there is an "Automated Action" related to your case. If so, open it and make it inactive by unchecking the field "Active". Try also to restart your server if necessary.

The Automated Actions section is completely empty

See also under "Settings ---> Technical ---> Actions ---> Server Actions"

I dont think there are any related actions. Sunder Server Actions, there are three items: "Deliver/Receive Products", "Module Immediate Install", and "Run Remaining Action Todo" (res.config object).