I am seeing the same thing, and have for several weeks. About a month ago my system was showing high usage, trending > than 1TB per month. I could not account for such high usage, and when looking at the usage for each device, they all showed <0.1% of monthly use. After several attempts I could not find anything using more internet than in previous months. I gave up spending time on it, and now pay for unlimited. Since that time, the usage has remained ridicuolously high. No streaming, no gaming, no downloads other than windows updates. Makes no sense, and I am convinced there is something wrong with the way this system tracks data use.