After auto-updating from version 1.2 to version 1.2.1 of the Gallery theme, I noticed that I continued to get a update notification to upgrade to 1.2.1. Each time I attempted to auto-update I got the same result. Out of desperation, I decided to download the latest version and install it manually. Same problem.
Finally I noticed that the version number in the style.css file of the most recent download file still makes reference to the old version as noted below:
Theme Name: Gallery
Theme Date: 20/12/2010
Theme URI: https://premium.wpmudev.org/
Description: A flexible gallery style theme for WordPress and BuddyPress using custom post types or a page template
Author: Tammie Lister - WPMU DEV - The WordPress Experts
Author URI: https://premium.wpmudev.org
WDP ID: 166
After changing the version number to 1.2.1, I immediately stopped getting the auto-update notification. I suspect this is just a matter of the developer forgetting to update the version number (as opposed to the wrong file,) since there is very little code in the file that might have changed. If I'm mistaken, please let me know so I can make sure I have the correct file.