I heard the rattle for the first time after being on skype...So once it heats up and separates the glue you are stuck with the rattle? If my phone has a scratch will they do the warranty replacement?
Mine only does it when its warm. Try it just after you have charged it or if you are talking for quite a long time. You can feel the back is very warm.
I just swapped my phone out for a new one. So far so good. The problem is getting all your apps and customization back the way you had it takes lots of time.