If this is occurring, the animation may just be the culprit that keeps breaking your build.
To test this theory out, please remove the animation and try to build your video without it. If it builds as intended then the animation was indeed the issue, and you can try to add the animation back (or another) and attempt the build again.
If it failed, no worries. Just reach out to us as you may have found a glitch in our matrix, and it'd allow us to fix the animation for you and everyone else. Unfortunately it may take a few hours, so if it's extremely urgent, we recommend using a different animation while we fix the broken one.