@PointC @akapowl Thanks. Updating the version did make it work. Since clip-path ellipse worked with the older version I was expecting the polygon one to work. Seems like upgrading is the only option.
The clip-path animation in the mentioned code pen is not working.
Can someone please point out what am I doing wrong? The other one with ellipse works just fine - https://codepen.io/sayaliga15/pen/abmpMdY