A Map Service from the StartupLayers uses antialiasing to symbolize red polygons. I copy the service to My Data and the symbology stays the same:

I close ArcGIS Earth and restart it. There is now a difference between the two services symbologies. The service from My Data now has some white and pink pixels:

It seems that the transparency is now gone (or somehow affected), and that we see white and pink pixels instead of transparent red pixels:

We also can see a difference in the labels :

Thank you.