I'll probably end up rewriting these serializers

src/main/java/com/gmail/nossr50/config/ConfigManager.java

@@ -261,6 +261,8 @@ public final class ConfigManager {
         customSerializers.registerType(new TypeToken<FormulaType>() {}, new CustomEnumValueSerializer());
         customSerializers.registerType(new TypeToken<MMOItem<?>>() {}, new ItemStackSerializer());
         customSerializers.registerType(new TypeToken<Set<?>>() {}, new SetSerializer());
+
+        customSerializers.registerType(new TypeToken<ItemMatch<?>>() {}, new CustomItemTargetSerializer());
         customSerializers.registerType(new TypeToken<SimpleRepairCost>() {}, new SimpleRepairCostSerializer());
 
         customSerializers.registerType(TypeToken.of(TamingSummon.class), new TamingSummonSerializer());
@@ -274,7 +276,6 @@ public final class ConfigManager {
         customSerializers.registerType(TypeToken.of(PlayerNotificationSettings.class), new PlayerNotificationSerializer());
         customSerializers.registerType(TypeToken.of(SoundSetting.class), new SoundSettingSerializer());
         customSerializers.registerType(TypeToken.of(ItemWildcards.class), new ItemWildcardSerializer());
-        customSerializers.registerType(TypeToken.of(ItemMatch.class), new CustomItemTargetSerializer());
         customSerializers.registerType(TypeToken.of(RepairTransaction.class), new RepairTransactionSerializer());
         customSerializers.registerType(TypeToken.of(RawNBT.class), new RawNBTSerializer());
     }

src/main/java/com/gmail/nossr50/config/hocon/serializers/CustomItemTargetSerializer.java

@@ -13,9 +13,9 @@ import org.checkerframework.checker.nullness.qual.Nullable;
 
 import java.util.HashSet;
 
-public class CustomItemTargetSerializer implements TypeSerializer<ItemMatch> {
+public class CustomItemTargetSerializer implements TypeSerializer<ItemMatch<?>> {
 
-    private static final String ITEM_CONSUMED_FOR_REPAIR = "Item-Consumed-For-Repair";
+    private static final String ITEM_CONSUMED_FOR_REPAIR = "Target-Item";
     private static final String NBT_REQUIREMENTS = "NBT-Requirements";
 
     @Nullable
@@ -32,7 +32,7 @@ public class CustomItemTargetSerializer implements TypeSerializer<ItemMatch> {
     }
 
     @Override
-    public void serialize(@NonNull TypeToken<?> type, @Nullable ItemMatch obj, @NonNull ConfigurationNode value) throws ObjectMappingException {
+    public void serialize(@NonNull TypeToken<?> type, @Nullable ItemMatch<?> obj, @NonNull ConfigurationNode value) throws ObjectMappingException {
         value.getNode(ITEM_CONSUMED_FOR_REPAIR).setValue(obj.getItem());
 
         if(obj.getItemMatchProperties().size() > 0) {