I recently purchased a Lumia 830 when Microsoft was running their $200 promo. After using it for a week with no problems I started noticing intermittent screen jumps while scrolling. I would describe this as text jumping vertically while scrolling which makes it difficult to read since I need to look for the text I was just reading. I noticed this same issue with a 1520 which I thought might be related to the tap scroll issue. Has anyone else had this issue with an 830? My daughter has a 635 and I never noticed any jumping while scrolling. Thanks.