Google map optimized property?

Hi all.
I’m trying to animate google map markers.
I have no back-end development background, just up till D3, and that was at least a year ago.

So far I’m managing in my project , but for some reason the Marker optimized property value stays yellow in codepen?

codepen

Not sure what I’m doing wrong, as the property is not deprecated and as far as I know I have added all the needed libraries.

Thanks