Comment 2 for bug 1631186

hmmm ... strange
today (7.10.2016) at 9:09 calendar sync passed, found all my calendars and synced successfully.
until 19:56. From this time syncing fails, as before.
until 20:04. Sync is successful again ...

Sometimes it fails, sometimes not ...
Maybe google has some limit for time between calendar syncs.
Appending todays sync-monitor.log