I think I ran into a bug. I think that Edges should be also hidden by a slice plane. Or is it on purpose? https://www.babylonjs-playground.com/#Y6W087#58
It is on purpose. We are not applying clipping planes to edge renderer
But we can add it if you want to create a feature request on the repo
@Evgeni_Popov could take a stab at it
Yes, I can have a look after I have finished unstacking my pending PRs.