well you just get 8+,so that is why it looks like this
Bugs [ ] [ ]: Stats Chart start and end date doesn't match selected day range+

There are 2 bugs in the plotting logic of the rating charts:
1. The start and end dates should match the range. In the above example 6/26 - 7/2. Not 7/1 - 7/2
2. If no games have been played, the the rating is the same as the rating of the last game played., as shown here
However for gaps where no game was played often the plot just connects the prior game day's rating with the next game day's rating. It should plot a flat line until the next game day's rating, then plot vertical line to that day's rating.
For example:
Here is an animated gif showing the issue:

Thanks for the detailed feedback. We're probably not going to fix these.
Why not! It is just wrong and clearly a bug.
The correct code exited before the "upgrade", so one could reference the code and appreciate what the fix is. As is stands it does not plot the correct date range if there are leading or trailing gaps.
For example the 7 day plot below only plots 2 days 7/1 and 7/2, the 2 days with games. There were no games from 6/26 thru 6/30. The plot should plot from 6/26 thru 7/2.
Here is the plot:
It should look similar to this: