Erika If you are playing an animation forward, it loops, if you click the reverse play button, it plays the animation just once in reverse. Spine 3.6 ob windows 10 🙂
Nate Weird, I see it looping in reverse, eg using spineboy-pro. It doesn't seem like it should be project-specific, but it's possible. What else could be going on? What views do you have open?