Same problem here, One day I put my phone to charge, and after a few minutes, i heard the USB connection noise, well, I didn't care about it.... but when I looked at the phone, i saw the screen was on, with a clock screensaver I've never seen before, then i find out that the phone was in Dock Station mode, I thought it might be a software bug, so I restarted the phone but then the phone was in MTP / charging mode (without any cable attached). In MTP mode i couldn't do anything with the phone, it kept trying to sync.... after a few restarts, the phone was working again, but then i noticed that the phone was continually charging the battery (again without any cables), and the battery went from 100% to 15% in about 5 hours. The next day I tried to turn the phone off, and i saw the temperature warning, and after trying to update, putting new rom, etc... I brought the phone to the shop, and they sent it to Samsung..... after 3 weeks the phone was back, with a new battery.... but when I came home, I putted the battery and the phone went on by it self, and after that, all my problems are back, the phone keeps charging it self, it keeps in MTP mode, I can't turn the phone off, because if I do, I get the battery temp. warning or it goes on again. The Samsung service is very disappointing, i can't send my phone for another 3 weeks for reparation.... if they don't give me another new phone, I'll start a legal complaint against the phone shop and Samsung to get my money back, and i will buy another phone, no samsung for me anymore.