3D Polyline not rendered correctly on web

[IsraelShpindel]

I have a 3D polyline layer, created with the Points to Line tool. The original points have Z values, and two of them have the same XY values but different Z value. I have also published the layers as feature layers in Portal for ArcGIS.

When I'm adding the feature layer to an ArcGIS Pro scene everything looks fine, but when adding it to a web scene in the portal, the line segment between the two vertices with the same XY value is missing. It seems like the map cannot display a perpendicular line and therefore it just skips one of the line's vertices.

Is that a known limitation of web scenes? What can I do to fix it?