Cartographic Polygon problem

I may be doing something completely wrong here, but I did follow your tutorial here:
Clipping Tilesets – Cesium

But when I try to clip out a section of a tile that is of any shape, it will remove the whole section of the tile.

My settings appear to be correct, unless this is the part I am misunderstanding.

Am I being stupid and missing something obvious here?

I’m using Cesium for Unreal v1.31.0 downloaded from GitHub with version 5.2.1 of Unreal Engine.

Thanks

(Edited to use correct settings image.)

It’s hard to tell what’s going on from your screenshot. Does this happen in Level 8 of the Cesium for Unreal Samples project, too?

Can you provide us with detailed instructions for reproducing the problem? Preferably starting with the Cesium for Unreal Samples project.