KTX2 roughness channel with ClampToEdge

[echadwick-artist]

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:
KhronosGroup/glTF-Sample-Assets#174

Thanks!

[UX3D-haertl]

I updated KTX to the newest version, but this did not fix the issue.
I checked the ktx files and it seems like the metallic roughness textures are sRGB instead of linear. Maybe this is the issue?
If I reconvert them via Gestaltor the issue disappears.