flip demo add data-style="flip-duration:500ms" not working

[beisu]

flip demo:

https://codesandbox.io/s/vue-flip-demo-xhtfk

add data-style="flip-duration:500ms" to <span data-view="flip"></span>

result: <span data-view="flip" data-style="flip-duration:500ms"></span>

then the flipping effects not working, pls

[beisu]

and, append <span data-view="text"></span> to flip view

result: <div data-repeat="true" aria-hidden="true"> <span data-view="flip"></span> <span data-view="text"></span> </div>

then the flip view disappeared

[beisu]