diff --git a/api/src/main/java/com/viaversion/viaversion/api/type/types/minecraft/FlatItemType.java b/api/src/main/java/com/viaversion/viaversion/api/type/types/minecraft/FlatItemType.java
index 9c6d90926..c718cca1c 100644
--- a/api/src/main/java/com/viaversion/viaversion/api/type/types/minecraft/FlatItemType.java
+++ b/api/src/main/java/com/viaversion/viaversion/api/type/types/minecraft/FlatItemType.java
@@ -26,6 +26,7 @@ import com.viaversion.viaversion.api.minecraft.item.DataItem;
 import com.viaversion.viaversion.api.minecraft.item.Item;
 import com.viaversion.viaversion.api.type.Type;
 import io.netty.buffer.ByteBuf;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 public class FlatItemType extends BaseItemType {
     public FlatItemType() {
@@ -33,7 +34,7 @@ public class FlatItemType extends BaseItemType {
     }
 
     @Override
-    public Item read(ByteBuf buffer) throws Exception {
+    public @Nullable Item read(ByteBuf buffer) throws Exception {
         short id = buffer.readShort();
         if (id < 0) {
             return null;
@@ -47,7 +48,7 @@ public class FlatItemType extends BaseItemType {
     }
 
     @Override
-    public void write(ByteBuf buffer, Item object) throws Exception {
+    public void write(ByteBuf buffer, @Nullable Item object) throws Exception {
         if (object == null) {
             buffer.writeShort(-1);
         } else {
diff --git a/api/src/main/java/com/viaversion/viaversion/api/type/types/minecraft/FlatVarIntItemType.java b/api/src/main/java/com/viaversion/viaversion/api/type/types/minecraft/FlatVarIntItemType.java
index 933d729dc..e1b3203d7 100644
--- a/api/src/main/java/com/viaversion/viaversion/api/type/types/minecraft/FlatVarIntItemType.java
+++ b/api/src/main/java/com/viaversion/viaversion/api/type/types/minecraft/FlatVarIntItemType.java
@@ -25,6 +25,7 @@ package com.viaversion.viaversion.api.type.types.minecraft;
 import com.viaversion.viaversion.api.minecraft.item.DataItem;
 import com.viaversion.viaversion.api.minecraft.item.Item;
 import io.netty.buffer.ByteBuf;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 public class FlatVarIntItemType extends BaseItemType {
     public FlatVarIntItemType() {
@@ -32,7 +33,7 @@ public class FlatVarIntItemType extends BaseItemType {
     }
 
     @Override
-    public Item read(ByteBuf buffer) throws Exception {
+    public @Nullable Item read(ByteBuf buffer) throws Exception {
         boolean present = buffer.readBoolean();
         if (!present) {
             return null;
@@ -46,7 +47,7 @@ public class FlatVarIntItemType extends BaseItemType {
     }
 
     @Override
-    public void write(ByteBuf buffer, Item object) throws Exception {
+    public void write(ByteBuf buffer, @Nullable Item object) throws Exception {
         if (object == null) {
             buffer.writeBoolean(false);
         } else {
diff --git a/api/src/main/java/com/viaversion/viaversion/api/type/types/minecraft/ItemType.java b/api/src/main/java/com/viaversion/viaversion/api/type/types/minecraft/ItemType.java
index 202efafff..1fce6b621 100644
--- a/api/src/main/java/com/viaversion/viaversion/api/type/types/minecraft/ItemType.java
+++ b/api/src/main/java/com/viaversion/viaversion/api/type/types/minecraft/ItemType.java
@@ -25,6 +25,7 @@ package com.viaversion.viaversion.api.type.types.minecraft;
 import com.viaversion.viaversion.api.minecraft.item.DataItem;
 import com.viaversion.viaversion.api.minecraft.item.Item;
 import io.netty.buffer.ByteBuf;
+import org.checkerframework.checker.nullness.qual.Nullable;
 
 public class ItemType extends BaseItemType {
     public ItemType() {
@@ -32,7 +33,7 @@ public class ItemType extends BaseItemType {
     }
 
     @Override
-    public Item read(ByteBuf buffer) throws Exception {
+    public @Nullable Item read(ByteBuf buffer) throws Exception {
         short id = buffer.readShort();
         if (id < 0) {
             return null;
@@ -47,7 +48,7 @@ public class ItemType extends BaseItemType {
     }
 
     @Override
-    public void write(ByteBuf buffer, Item object) throws Exception {
+    public void write(ByteBuf buffer, @Nullable Item object) throws Exception {
         if (object == null) {
             buffer.writeShort(-1);
         } else {
diff --git a/api/src/main/java/com/viaversion/viaversion/api/type/types/version/PaletteType1_18.java b/api/src/main/java/com/viaversion/viaversion/api/type/types/version/PaletteType1_18.java
index 1d588a7b6..f3653f14a 100644
--- a/api/src/main/java/com/viaversion/viaversion/api/type/types/version/PaletteType1_18.java
+++ b/api/src/main/java/com/viaversion/viaversion/api/type/types/version/PaletteType1_18.java
@@ -42,12 +42,8 @@ public final class PaletteType1_18 extends Type<DataPalette> {
 
     @Override
     public DataPalette read(final ByteBuf buffer) throws Exception {
-        int bitsPerValue = buffer.readByte();
-        final int originalBitsPerValue = bitsPerValue;
-
-        if (bitsPerValue > type.highestBitsPerValue()) {
-            bitsPerValue = globalPaletteBits;
-        }
+        final int originalBitsPerValue = buffer.readByte();
+        int bitsPerValue = originalBitsPerValue;
 
         // Read palette
         final DataPaletteImpl palette;
@@ -59,6 +55,12 @@ public final class PaletteType1_18 extends Type<DataPalette> {
             return palette;
         }
 
+        if (bitsPerValue < 0 || bitsPerValue > type.highestBitsPerValue()) {
+            bitsPerValue = globalPaletteBits;
+        } else if (type == PaletteType.BLOCKS && bitsPerValue < 4) {
+            bitsPerValue = 4; // Linear block palette values are always 4 bits
+        }
+
         if (bitsPerValue != globalPaletteBits) {
             final int paletteLength = Type.VAR_INT.readPrimitive(buffer);
             palette = new DataPaletteImpl(type.size(), paletteLength);
@@ -70,14 +72,15 @@ public final class PaletteType1_18 extends Type<DataPalette> {
         }
 
         // Read values
-        final long[] values = new long[Type.VAR_INT.readPrimitive(buffer)];
-        if (values.length > 0) {
-            final char valuesPerLong = (char) (64 / bitsPerValue);
+        final int valuesLength = Type.VAR_INT.readPrimitive(buffer);
+        if (valuesLength > 0) {
+            final int valuesPerLong = (char) (64 / bitsPerValue);
             final int expectedLength = (type.size() + valuesPerLong - 1) / valuesPerLong;
-            if (values.length != expectedLength) {
-                throw new IllegalStateException("Palette data length (" + values.length + ") does not match expected length (" + expectedLength + ")! bitsPerValue=" + bitsPerValue + ", originalBitsPerValue=" + originalBitsPerValue);
+            if (valuesLength != expectedLength) {
+                throw new IllegalStateException("Palette data length (" + valuesLength + ") does not match expected length (" + expectedLength + ")! bitsPerValue=" + bitsPerValue + ", originalBitsPerValue=" + originalBitsPerValue);
             }
 
+            final long[] values = new long[valuesLength];
             for (int i = 0; i < values.length; i++) {
                 values[i] = buffer.readLong();
             }