When you set the iPhone to Set Automatically, it gets the time from the cell network and updates it based on your time zone. I'm not sure what advice to give since I have the exact same phone and software and am having no issues myself. What is your location when this happens?
I had the same thing happen to me at Metrotown and one spot in Richmond, but not anywhere else in Vancouver I've been. Do you find it's geographical? Fido tech support told me it's "an iPhone bug", but if it's geographical it must be some setting on the cel phone tower.
this is happening since ios 5 upgrade. although i may not have noticed it before. but we are in saskatchewan, and our out set timezone goes to winnipeg. it is really frustrating. if tried every combination of re-set and toggling flight-mode on off etc. etc.
i have an iPhone 4, and when it is sent to auto set time zone, it sets it to Winnipeg, despite the fact that i am in Saskatchewan.
On my wife's iPhone, this has caused all of her calendar events to change to being 1 hour late. this is a major problem.
i have done a pretty thourogh search on apple support boards and user groups, and the consensus is that the problem lies with the rogers/fido network. any help with this would be greatly appreciated.