it happend several times before (about once a month) that Piwik shows in my dashboard naught visitors at the end of a certain day althought there were visitors. The interesting thing about this is that Piwik tracked every single visitor that day, but the VisitSummary stays empty (even the days after). On the summary of the month this day is also treated as a “no-visitors-day”. You can see it on the attached image.
Is that an error I can fix on my own or is it a bug?