@KarnFar and others maybe you can help me work this out. Here’s what I see...
It appears to me that Apple created a feature to display (time/time zone) in each event IF the time zone is different from the time zone of the Calendar app. (Perhaps this was a new feature in iOS 8 and Yosemite, but I can’t remember how things used to work in earlier OS versions.) So, now the logic is as follows...
When the time zone of the Calendar app and the event are the same, no alternate (time/time zone) appears.
When the time zone of the Calendar app and the event are different, (time/time zone) appears to display the event’s original time and time zone.
Along the way, in iOS 8 and Yosemite, new Calendar events sync to the time and time zone of the service and thus displayed (GMT time/GMT) when the Calendar app was not in GMT. It then appears that Google has now changed this to point to the user’s Google Calendar Time zone and instead of the Google base time zone and voila!, here we are… if your Calendar app and Google Calendar are in the same time zone, which they typically are, then (time/time zone) disappears from the events. As @KarnFar points out, there is a nice shortcut for cleaning up a batch of past events that got shifted to GMT.
However, I think there is still a bug - shouldn’t a new event retain the time zone of the Calendar app rather than the service it’s syncing to? In fact, when you change the time zone for an event, the new time zone is saved (as expected) and the logic outlined above still applies. I’m hoping that the 8.2 release fixes this apparent bug so that new events adopt the time zone of the Calendar app (whether the time zone comes from iOS or Mac OS or the Time Zone Override) rather than the calendar service. That seems like a more consistent behavior to me anyway.
Thoughts anyone?