There isn’t a easy way to look at the individual leg history today, though from some videos, it does exist back at the Sense mothership (or if you are industrious with Python, you can build your own L1/L2 sampler using the informal API). But if you have a smart meter, you are likely to be able to pull some kind of time history from your utility, with either daily, hourly or even 1/4 hourly data. That can be used to isolate an intermittent difference between Sense and your utility.