KTX2 roughness channel with ClampToEdge

When a KTX2 texture is using ClampToEdge for the sampler, the glTF Sample Viewer is rendering the Roughness channel incorrectly.

KTX2 textures, compared in glTF Sample Viewer (left) and Babylon.js Sandbox (right):

KTX2 textures, roughness alone:

PNG textures do not show the issue:

WebP textures do not show the issue:

Relevant parts of the glTF:

Example asset showing the issue:
https://github.com/KhronosGroup/glTF-Sample-Assets/pull/174

Thanks!