Google Analytics Outage 16/09 23:00 - 17/09 06:00?

Noticed some huge irregularities in my Google Analytics tracking data between these times suggesting a server outage, contrary to the data from my nginx logs.
This doesn't seem to have affected all my websites so I was wondering if anyone else has experienced anything similar.

Cheers,
JFoulds

Well, I got an email that they made a bunch of changes live .. maybe it was part of the switchover? I haven't seen anything irregular.