[07Aug2020 06:49:43.079] [Worker-Main-9/ERROR] [net.minecraft.item.crafting.RecipeManager/]: Parsing error loading recipe carpetstairsmod:mushroom_wood_floor
com.google.gson.JsonSyntaxException: Unknown item 'extendedmushrooms:mushroom_slab'
at net.minecraft.item.crafting.Ingredient.lambda$deserializeItemList$11(Ingredient.java:216) ~[?:?]
at java.util.Optional.orElseThrow(Unknown Source) ~[?:1.8.0_261]
at net.minecraft.item.crafting.Ingredient.func_199803_a(Ingredient.java:215) ~[?:?]
at net.minecraftforge.common.crafting.VanillaIngredientSerializer.parse(VanillaIngredientSerializer.java:41) ~[?:?]
at net.minecraftforge.common.crafting.CraftingHelper.getIngredient(CraftingHelper.java:155) ~[?:?]
at net.minecraft.item.crafting.Ingredient.func_199802_a(Ingredient.java:189) ~[?:?]
at net.minecraft.item.crafting.ShapedRecipe.func_192408_a(ShapedRecipe.java:252) ~[?:?]
at net.minecraft.item.crafting.ShapedRecipe.access$000(ShapedRecipe.java:24) ~[?:?]
at net.minecraft.item.crafting.ShapedRecipe$Serializer.func_199425_a_(ShapedRecipe.java:276) ~[?:?]
at net.minecraft.item.crafting.ShapedRecipe$Serializer.func_199425_a_(ShapedRecipe.java:272) ~[?:?]
at net.minecraft.item.crafting.RecipeManager.func_215377_a(RecipeManager.java:141) ~[?:?]
at net.minecraft.item.crafting.RecipeManager.func_212853_a_(RecipeManager.java:61) ~[?:?]
at net.minecraft.item.crafting.RecipeManager.func_212853_a_(RecipeManager.java:38) ~[?:?]
at net.minecraft.client.resources.ReloadListener.func_215269_a(SourceFile:13) ~[?:?]
at java.util.concurrent.CompletableFuture.uniAccept(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture$UniAccept.tryFire(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture$Completion.run(Unknown Source) ~[?:1.8.0_261]
at net.minecraft.resources.AsyncReloader.func_219557_a(SourceFile:71) ~[?:?]
at net.minecraft.resources.AsyncReloader.func_219560_a(SourceFile:70) ~[?:?]
at java.util.concurrent.CompletableFuture$UniCompletion.claim(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture.uniAccept(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture$UniAccept.tryFire(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture.postComplete(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture.postFire(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture$UniAccept.tryFire(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture$Completion.run(Unknown Source) ~[?:1.8.0_261]
at net.minecraft.resources.AsyncReloader.func_219557_a(SourceFile:71) ~[?:?]
at net.minecraft.resources.AsyncReloader.func_219560_a(SourceFile:70) ~[?:?]
at java.util.concurrent.CompletableFuture$UniCompletion.claim(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture.uniAccept(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture$UniAccept.tryFire(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture.postComplete(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture.postFire(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture$UniAccept.tryFire(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture$Completion.run(Unknown Source) ~[?:1.8.0_261]
at net.minecraft.resources.AsyncReloader.func_219557_a(SourceFile:71) ~[?:?]
at net.minecraft.resources.AsyncReloader.func_219560_a(SourceFile:70) ~[?:?]
at java.util.concurrent.CompletableFuture$UniCompletion.claim(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture.uniAccept(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture$UniAccept.tryFire(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture.postComplete(Unknown Source) ~[?:1.8.0_261]
at java.util.concurrent.CompletableFuture.complete(Unknown Source) ~[?:1.8.0_261]
at net.minecraft.resources.AsyncReloader$1.func_216873_a(SourceFile:53) ~[?:?]
at net.minecraft.resources.AsyncReloader$1.func_216872_a(SourceFile:50) ~[?:?]
at java.util.concurrent.CompletableFuture.uniCompose(Unknown Source) [?:1.8.0_261]
at java.util.concurrent.CompletableFuture$UniCompose.tryFire(Unknown Source) [?:1.8.0_261]
at java.util.concurrent.CompletableFuture.postComplete(Unknown Source) [?:1.8.0_261]
at java.util.concurrent.CompletableFuture$AsyncSupply.run(Unknown Source) [?:1.8.0_261]
at java.util.concurrent.CompletableFuture$AsyncSupply.exec(Unknown Source) [?:1.8.0_261]
at java.util.concurrent.ForkJoinTask.doExec(Unknown Source) [?:1.8.0_261]
at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(Unknown Source) [?:1.8.0_261]
at java.util.concurrent.ForkJoinPool.runWorker(Unknown Source) [?:1.8.0_261]
at java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source) [?:1.8.0_261]

There are several such errors in the console log

running forge 1.16.1 ...-106 with version "Carpet Stairs Mod mc1.16.1 v1.4.6"