I have this same problem. In the StatComm page, the Overview is showing wrong info. One of the days (the bars) show 0 to everything but the spiders, but I had many hits that day, unique visitors, and so on, that on the day itself it was showing.
Strangely, in the Details page, the unique visitors, for example, show the correct number for that specific date.
Also, in the overview, the “This Month” and “Yesterday” Columns also show different numbers than the “Details page” for the unique visitors…
I have the “jetpack” installed, with the statistics. This could cause any kind of trouble with StatComm?