I’m using Apple Mail, from both mobile and desktop, (currently from my phone) I see my replies as another email in the given conversation like any other replies. Must be a setting you have turned on or off in your mail preferences.

Tony

OK, you all convinced me. I’m not sure what is going on then. To be clear, Apple Mail (in OS X and iOS) WILL pull your original sent message from the Sent folder and put it in the thread for you- so you have to be careful… -andy