You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
They've said they don't change. It may have just picked up the next set of words
The GPS signal is not as stable indoors. It is more accurate used outdoors when you can get line of sight to the sky. If you think your location on the map is not correct, switch to satellite view and move the highlighted square manually, to refine its position.
Thank you 
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.
