Steps to reproduce:
1. Open up any Sprites animation.
2. Right click in the Animations list and add a new animation, and then select this animation.
3. Click the "Open" icon at the top right of the Animation Editor and load any image.
4. On the animation bar, right click and add another Animation
5. Type in a name for the animation and click off/hit enter. Volia, the name of the first animation in the list will get changed instead!
Also, since it's quite probable that this relates to the same bug, it seems that after using that "Open" button, if you click onto another animation, it will instead select the FIRST animation.