I have been suffering from this issue since the day that iOS 8 came out; yes this was happening on my 5S running iOS 8. This isn't an iPhone 6 issue, it's an iOS 8 issue. I have found that if I create the event in Google, in any way, it shows on my iOS devise correctly. Mobile or not. So, I still use my iOS 8 calendar app on both my iPad and iPhone 6+ but I never add any events through this beccause it will display the GMT thing. It shows up in the correct time slot on my calendar but because it shows the GMT thing I fear that the calendar will switch the event or the "alert" will not sound at the correct time. So to answer your question as to will someone try this, I have tried it and it works fine. The error occurs when the event is created on an iOS device, uploaded to Google, then synced back to the iOS device. If you watch after adding the event, the event will show in the correct time slot and there will be no GMT label as your "progress" dial spins while the event is sent to Google and back to the iOS device but once the sync has completed, violá you have a GMT tag. Something in the upload/download or "sync" is getting corrupt and defaulting to GMT (Google's Master Time, haha).
My fix for this, go to calendar.google.com and create an icon on the home screen, with the share button, then you have quick access to your mobile version of the calendar and if you add something this way, it will display correctly and without the GMT tag on the iOS devise (at least it does for me so I add all new events from my phone in this manner). If I add the event through my laptop using Safari, Chrome or FireFox it will display correctly on my iOS device. If I use the mobile version of my calendar in Safari or Chrome on my both my iPad and iPhone, the event will display correctly. If I use the desktop version on my iPad using Safari or Chrome, it will display correctly on my iOS device. The only time I experience this problem is when I add the event in the native iOS Calendar, from either device. So it's a giant pain in the rear (and time consuming to some degree) to be looking at my calendar in iOS and then having to flip over to the Google mobile version to add the event and then back to the calendar to go on but since Apple and Google can't play nice on this issue, it's a neccesary evil to ensure I am not late or miss a client meeting all together.