I have read every single entry in this thread and NONE of the "solutions" worked for me. To be perfectly clear I had my new phone with ios 8 for 32 days and did not have this issue. I didnt make any changes or do any updates to phone and just one random day, the gmt bug got me. Nearly every day at my office a new person catches this bug (without changing any settings) and everyone is going mad! Our shared calendars are totally screwed! The only work around that is half way reasonable is to make an appointment as an all day event (ending the same day) and for some reason all day events are immune to the gmt bug.
Appointments made in gmail sync to iphone/ipad without gmt issue. Events input in iphone/ipad immediately change to gmt on device but sync to gmail correctly.
Myself and several others in my office have tried:
Verified and reverified and reverified that time zone is correct on device(s) and gmail. It doesnt say gmt anywhere.
Turning on and off time zone over ride.
Turning on and off setting time zone automatically (and every combination of the two)
Removing and reinstalling google. (several times)
Removing google and installing exchange (still had the issue)
Change default calendar to hotmail (which I dont use at all for work, etc) and still had the issue.
Switching several appointments from GMT to my time zone to see if all appts would change- they didnt
Hard reset of phone
Factory reset of phone restoring from backup.
I am sure there are other suggestions we tried as well but none worked.
This is a bug and it is ridiculous Apple would even dare to imply this feature is intentional- especially since the problem doesnt impact the icloud calendar.