This issue is already reported on Github: Missing metrics and reports · Issue #12251 · piwik/piwik · GitHub
Hi! One of my websites has the Canary timezone. It was working great until the time change from summer to winter time. When this happened, all the data shows perfectly until the begining of the next day, at that moment all metrics from the day before are set to zero in all widgets.
In summary: the current day shows all reports and metrics correctly. When the next day starts, all data of the day before is set to zero. And Piwik keeps this behavior everyday.
I checked the database (piwik_archive_numeric_2017_XX) and I believe that Piwik is building the last archive of the day without calculating any metric, so, it says “done” and it’s set to 1 (definitive, not temporarily or invalid or with errors) but there are no metrics calculated at that moment.
My workaround has been to set the “done” register to 2 or 4 and force Piwik to archive the site for that day. But obviously there has to be a better solution to prevent this issue to happen.