If you’ve been using Google Calendar on your iPhone, you may have experienced the GMT bug. This is where your calendar entry shows up in GMT time zone, including when trying to edit the item. If you add an appointment for example for 1pm in New York City, click save, then go back to view it, it would have shown up with the GMT time equivalent along with your current time zone. If you choose to edit the time, then it only showed the GMT time.
The issue was so widespread that this Apple discussion forum has had over 321k views, as of this post.
Some had thought this was an iOS bug but it appears to have been on the backend with Google since it was fixed without any new update from Apple. If your time zones are still showing GMT for a Google account, I would recommend going into Settings and removing the calendar account and then adding it back. That seemed to have solved it for me.
Tech Spinning 