Hello,
Thanks for reaching out! The animation is actually applied to the menu button (if you have a single button it applies to the one singular button since there is no separate menu button). So, if you create two buttons in the same group without using a menu button, the animation isn't applied to anything. On the other hand, if you made a "contact" menu button that opened to the call and schedule button, then the "contact" menu button would have the same animation successfully applied.
It's probably not intuitively obvious that the animation applies to the menu button if you had been using just a single button to start, but that would be the reason for the difference you are currently seeing. I did mark your question as a feature request to add animations to individual buttons when using multiple buttons without a menu button as well.
Hope that clarifies!