Unfortunately, fixing this bug caused a larger problem: sending cookies securely from HTTPS pages meant that HTTP pages could no longer read the cookies, causing the cookies to be regenerated. As a result, Snowplow’s
domain_userid field (the first-party user ID) was being reset when a user browsed from an HTTPS page (e.g. checkout) back to an HTTP page.
So, this release fixes a nasty bug. Thanks to the Piwik team for their help in brainstorming this problem!