The steep oblique ebony and mahogany fences from XKdeco are not craftable; their recipes produce their regular oblique counterparts instead. This can be easily fixed by just overriding the recipes with ones that output the right items using KubeJS.

I would report this to XKdeco's dev... if they had a repo, which they do not. As such, I figured I'd ask if C:A&B could include the fixed recipes.