I would say take it back. But try and turn off the LG IME first and let me know if that helps anything. Even if it does fix it, I would take it back, there is a software issue on your phone and right now there is no updates or firmware, you are probably running 10c right now, the only other thing I would suggest would be to try and reinstall the 10c firmware, follow the instructions in the "spacebar problem, black screen problem" thread in this forum, it will walk you through how to reinstall the 10c firmware.
But once again, you shouldn't have to find a fix to these problems, take it back and get a new one. As much as I love this phone, there is software issues with it that LG needs to resolve! Hope this helps.
