To the best of my knowledge, you have never been able to forward text messages to an email address, only able to forward the text to another phone #. Not on an iPhone at least.
Update: I tried it and it does work. The recipient sees the email coming from the phone#'s MMS email assigned by the carrier.
You can forward an SMS to an email address. When you say it is coming back to you, is the email you are trying to send to the email address of your Apple ID? Or, is this an email address that you are picking up on your iPhone? If you are selecting the portion of the message you want to forward and then entering the email address into the To: section, it should send to the email.
sometimes yes it is the Apple ID e-mail.
I just tried something. I have another e-mail that i access directly thru GMAIL, and I was able to forward the string to that e-mail and it worked fine.
both of the e-mail accounts i have are loaded on my iphone. It's as if the "to" field is defaulting to the associated phone number of the e-mail account, which is of course me.