Originally reported by changwan@ in 

https://bugs.chromium.org/p/chromium/issues/detail?id=911735&can=2&start=0&num=100&q=owner%3Ame&colspec=ID%20Pri%20M%20Stars%20ReleaseBlock%20Component%20Status%20Owner%20Summary%20OS%20Modified&groupby=&sort=&hotlist_id=

The documentation need to be cleared out here as well as enabling the Event Sync job: 

https://chromium-review.googlesource.com/c/infra/infra/+/1369479

This will create missing Calendar events during the event sync.