I have the 22.007 firmware and have had this issue with the original as well as this firmware. If I compose a message and sen it to one person in the to field and then nine (9) others in the BCC field, the message gets sent 10 times. So if I put 5MB of attachments in the message, I will need to send roughly 50MB of date. It will send it to the first person in the to field, then the second message it sends is to the first person in the BCC field. The third message will be the second person in the BCC field, the fourth message to the third person in the BCC and so on. This is not how an email client is suppose to be behave. I have an unlimited plan, but still, this is absurd. It takes forever to send anything and kills the battery.
I know the message gets sent multiple times because the mail server keeps a record of every copy I see that only change it who it is being sent to; one recipient at a time, so it is the phone doing this. I also can look at the connection log and I see the data connection as being active and how much has been sent.