We're running VisitorID v1.8, which was released 9/2016. The November
release included v1.9, with some notes referencing cross domain issues
that it fixed.Fixed a bug that prevented the ID service from passing the
Marketing Cloud ID (MID) across different domains. (MCID-215)So you may
be correct, however I'd expect more people reporting issues. FWIW, we
are also running AppMeasurement v1.7, the most current version.