I have encountered an issue with the material list with different schematics, always the same issue. The schematics are small in size, but include blocks from the create mod.
The issue that keeps appearing is that certain block states and even some entire blocks are not listed at all.
However they are rendered in the placed schematic in the world.
The blocks I have encountered this with as of now are all funnels, and pipes that are changed to a windowed one.

Just retested this with a schematic just including funnels, this works flawlessly, until the funnels point into a depot.
So a depot in front below the funnel makes the funnel not be shown in material list anymore:
test.zip
only mod needed is Create

• Minecraft version: 1.20.1
• Fabric version: 0.14.22
• Mod version: litematica-fabric-1.20.1-0.15.3
• malilib version: malilib-fabric-1.20.1-0.16.2