Has anyone noticed their touchscreen being unresponsive (in other words its like their is lag and it's sticking and you have press down harder than normal for something to register) from time to time? This has occurred while I texting or just trying to scroll through the different screens. Generally when this happens I press the power button on top and press it again and it seems to go away. Anyone experiencing this? I have a stock phone with no apps installed aside from Google Maps from the Market.