APL animation only lasts as long as ssml

Creating an alexa skill with APL. I have some uses of AnimateItem in the apl document I'm sending. If the output speech is very long, the whole animation renders. If it is short, it ends right as the speech ends. Is this intended? I want to render the whole animation.

"onMount": [
    {
    "type": "AnimateItem",
    "easing": "ease-out",
    "duration": 3000,
    "value": {
        "property": "opacity",
        "from": 0,
        "to": 1
    }
},]

I noticed this in the response json "timeoutType": "SHORT" Could this have something to do with it?