I noticed that the MultiSite dashboard shows up e.g. 10 visitors for today (July 19) but for week July 19 - 25 nothing. Same with pageviews and unique visitors.
Seems that the week does not include today. Maybe tomorrow figures from today will be shown. Will check this.
I checked the figures today. Now I have figures from yesterday and today if I select week. Maybe there is some failure in the calculation on the first day of the week.