mods/ITEMS/mcl_lectern/init.lua

@@ -130,9 +130,9 @@ end
 minetest.register_craft({
 	output = "mcl_lectern:lectern",
 	recipe = {
-		{"group:slab", "group:slab", "group:slab"},
+		{"group:wood_slab", "group:wood_slab", "group:wood_slab"},
 		{"", "mcl_books:bookshelf", ""},
-		{"", "group:slab", ""},
+		{"", "group:wood_slab", ""},
 	}
 })
 

mods/ITEMS/mcl_stairs/api.lua

@@ -71,8 +71,6 @@ end
 -- Node will be called mcl_stairs:stair_<subname>
 
 function mcl_stairs.register_stair(subname, recipeitem, groups, images, description, sounds, blast_resistance, hardness, corner_stair_texture_override)
-	groups.stair = 1
-	groups.building_block = 1
 
 	if recipeitem then
 		if not images then
@@ -92,6 +90,9 @@ function mcl_stairs.register_stair(subname, recipeitem, groups, images, descript
 		end
 	end
 
+	groups.stair = 1
+	groups.building_block = 1
+
 	minetest.register_node(":mcl_stairs:stair_" .. subname, {
 		description = description,
 		_doc_items_longdesc = S("Stairs are useful to reach higher places by walking over them; jumping is not required. Placing stairs in a corner pattern will create corner stairs. Stairs placed on the ceiling or at the upper half of the side of a block will be placed upside down."),