same here. i dont no why its doing it. but i have a guess that theres a setting in gmail(browser) that will turn this off. but i havnt looked yet

 

This is a known issue with the Blackberry email client and Gmail. But the workaround there is to filter the email using your carrier's BIS site. I don't have an answer for you, but gathering more information from you couldn't hurt.

Is this your first mobile device to access your Gmail account? If not, what where you using before, and did you have to make any special accommodations for that device?

Are you using a Gmail account or a Google Apps account? (I know you said Gmail, but I just want to clarify)

Gmail's filters are also applied to outgoing messages. Because of the way most people setup their filters, outgoing messages don't usually trigger the filters. Do you have any filters that might be triggered by outgoing messages?

Does this happen when you send email using Gmail's browser-based interface on your desktop, or the browser-based interface on your Droid?

Any information you can provide that might help determine what you have in common with others having the same experience would help.