I have struggled with similar problems since more than a week: battery draining much faster than before, time display in the upper right corner lagging behind (while the Clock app always showed the correct time), and besides that the data transfer via the USB connection refused to work. To my surprise, my phone is back to normal behaviour since yesterday! And I didn’t do any reset or what. I only inserted a micro-SD card, so I would be able to make a backup on it, And I dropped the phone accidentally, causing the battery to fall out another time. Perhaps this fumbling around did reset the battery in some way, or it removed some dust from the electrical contacts… But would it be just coincidence that several people see similar things at the same time? I’ll be following the news in this topic.