Norel
If you have looked at the stats graph, and then exit from that page via the red cross at the top right, then some time later click on the orange ball in the task bar, it will reopen on the stats screen, but it is the one you were looking at before, it hasn't updated to the current time.
Clicking on the statistics tab on the left will change the time period to "last week" and then resetting this to "today" updates the screen to the current stats.
I'm not sure what you mean about your graph showing smaller five minute intervals between the 2 hous markers. Mine looks like this: