Hi Derek,
We are experiencing the same issue with the Summary Widget as others above. When using the the widget it will sometimes double the expected count. It seems to be linked to the filtering within the Widget when switching between the set filters.
I reached out to ESRI customer support on this a couple weeks back (#BUG-000104093) and the workaround given was to wiggle the map around until it corrects itself. While that does work, it is not really a viable solution for us.
If we were to just disable the Filtering option within the Widget, would we still see any doubling in our data? (I ask this because I have seen it double the count upon opening a map, prior to touching the filter.) In my testing I have not seen this occur, but I need to be 100% sure before we go live with this particular map.
Thank you!