Looks like the project folder I have updated has "Loop" enabled on that animation for some reason, even though my local copy and the compiled version does not.
This was my first project using GD5, so it has a lot of bad practices in it. I'm currently working on remaking this using all of the stuff I've learned over the past year or so, so I would say wait for that. But I'm uploading a copy with this fixed. As mentioned, you can just open the hero object and uncheck the loop option to avoid this.
The fixed project has now been uploaded.