I've formed an idea on a possible solution*I installed twrp recovery via terminal emulator & have done some testing. I immediately made a backup & checked where it was stored after rebooting my phone and it is stored on the internal SD card. Although, if you check a box under mounts twrp will read from your external sd card & install any zips you may have stored there. I then rebooted back into twrp recovery & wiped cache, dalvik, and did a factory reset. To my surprise I was still able to restore my backup because twrp doesn't wipe your internal sd card storage or media? To my recollection cwm wipes everything including your internal sd card, at least on the gs3? So I believe perhaps cwm is what is wiping the area of our device that contains our imei data? This is at least possible, because I haven't read any reports of anyone using twrp having this issue. I've even scoured different sites asking users in twrp related topics if anyone has heard of the issue, and I've been all over searching high & low for ppl with our problem. My next step is to take the leap into installing many roms from the Tmo development section later this evening (hopefully). I may try to install & restore from them all. I will report my results back & if all is well each individual may make their own decision as to whether they feel comfortable installing twrp & flashing away! As for why cwm is wiping the imei(if it in fact is) I haven't the faintest clue, nor do I know how those already effected will recover other than a warranty exchange, but maybe we can at least prevent any other instances?