Lines not rendering well in arcgis online

[Oliver_Burdekin]

Using ArcGIS Pro 2.0 I've made a scene using a contour feature class. In ArcGIS Pro the contours look like this:

Sharing the scene to ArcGIS Online the rendering is poor and the same contours look like this:

Is there a way to increasing the resolution when sharing to AGOL?

UPDATE

I found this article on line aliasing. It hasn't helped.

[Lake_Country_GIS]

I also have the same problem. They look terrible: