I see almost identical spikes and dips during the exact same time period shown in your photo (10/29-11/2). I wrote it off to data glitches Sense suffered during those days?
An after thought is that it was particularly windy during that time period. So maybe Mother Nature and not Sense?
I think unless you start to see high/low events regularly, you are probably fine. There are a lot of reasons that your power supply could dip. Storms, Hot days, a hiccup at your transformer, a hiccup at the power company etc…
So having one or two events and only on one day probably means it was a one off type of thing.
If you start to get lots of low or high voltage events, then I would start to question it more and possibly involve your power company.