mod version: shutter-2.0.6-1.20.1
platform: forge
Willow shutter can only be obtained via command. it doesn't appear in a creative tab, JEI, and is uncraftable.
Kind of confusing, because Willow is the only one missing, even rest of the woodtype from the same mod are working fine.

Sorry, environmental is not updated to 1,20.1 so the willow slab that should have been used for recipe cant be used. So the shutter cant be optained otherwise

So... you mean that shutter was meant to be for Environmental's willow, not for Biome Makeover's?

Ok... environmental just got update, and it's working now....