Strange! I assume you’re running the latest firmware version? There is a flag you can include inside the animation CONFIG.INI that will force the animation to always finish before progressing, regardless of the timer setting.
finish = true
That’s how it looks. Are you using that? The fact that they don’t come up in sequential or shuffle is odd though. They definitely should. Makes me think there’s an issue with the folder names and they’re not being detected. What are you folder names? Maybe provide a zip of one of the animations.