diff --git a/projects/core-api/src/main/java/dan200/computercraft/api/lua/IArguments.java b/projects/core-api/src/main/java/dan200/computercraft/api/lua/IArguments.java
index 3f3e0f894..336f0b926 100644
--- a/projects/core-api/src/main/java/dan200/computercraft/api/lua/IArguments.java
+++ b/projects/core-api/src/main/java/dan200/computercraft/api/lua/IArguments.java
@@ -479,9 +479,11 @@ default String optString(int index, @Nullable String def) throws LuaException {
      * yourself.
      *
      * @return An {@link IArguments} instance which can escape the current scope. May be {@code this}.
-     * @throws LuaException For the same reasons as {@link #get(int)}.
+     * @throws LuaException          For the same reasons as {@link #get(int)}.
+     * @throws IllegalStateException If marking these arguments as escaping outside the scope of the original function.
      */
     default IArguments escapes() throws LuaException {
+        // TODO(1.21.0): Make this return void, require that it mutates this.
         return this;
     }
 }
diff --git a/projects/core/src/main/java/dan200/computercraft/core/apis/http/options/AddressPredicate.java b/projects/core/src/main/java/dan200/computercraft/core/apis/http/options/AddressPredicate.java
index ce4760452..25252a518 100644
--- a/projects/core/src/main/java/dan200/computercraft/core/apis/http/options/AddressPredicate.java
+++ b/projects/core/src/main/java/dan200/computercraft/core/apis/http/options/AddressPredicate.java
@@ -70,7 +70,7 @@ public static HostRange parse(String addressStr, String prefixSizeStr) {
             } catch (IllegalArgumentException e) {
                 LOG.error(
                     "Malformed http whitelist/blacklist entry '{}': Cannot extract IP address from '{}'.",
-                    addressStr + '/' + prefixSizeStr, prefixSizeStr
+                    addressStr + '/' + prefixSizeStr, addressStr
                 );
                 return null;
             }
diff --git a/projects/core/src/main/java/dan200/computercraft/core/asm/LuaMethodSupplier.java b/projects/core/src/main/java/dan200/computercraft/core/asm/LuaMethodSupplier.java
index 11f8e4310..7058ed5b5 100644
--- a/projects/core/src/main/java/dan200/computercraft/core/asm/LuaMethodSupplier.java
+++ b/projects/core/src/main/java/dan200/computercraft/core/asm/LuaMethodSupplier.java
@@ -21,7 +21,10 @@
  */
 public final class LuaMethodSupplier {
     private static final Generator<LuaMethod> GENERATOR = new Generator<>(LuaMethod.class, List.of(ILuaContext.class),
-        m -> (target, context, args) -> context.executeMainThreadTask(() -> ResultHelpers.checkNormalResult(m.apply(target, context, args.escapes())))
+        m -> (target, context, args) -> {
+            var escArgs = args.escapes();
+            return context.executeMainThreadTask(() -> ResultHelpers.checkNormalResult(m.apply(target, context, escArgs)));
+        }
     );
     private static final IntCache<LuaMethod> DYNAMIC = new IntCache<>(
         method -> (instance, context, args) -> ((IDynamicLuaObject) instance).callMethod(context, method, args)
diff --git a/projects/core/src/main/java/dan200/computercraft/core/asm/PeripheralMethodSupplier.java b/projects/core/src/main/java/dan200/computercraft/core/asm/PeripheralMethodSupplier.java
index 174b4ef19..ca7fa8ff3 100644
--- a/projects/core/src/main/java/dan200/computercraft/core/asm/PeripheralMethodSupplier.java
+++ b/projects/core/src/main/java/dan200/computercraft/core/asm/PeripheralMethodSupplier.java
@@ -22,7 +22,10 @@
  */
 public class PeripheralMethodSupplier {
     private static final Generator<PeripheralMethod> GENERATOR = new Generator<>(PeripheralMethod.class, List.of(ILuaContext.class, IComputerAccess.class),
-        m -> (target, context, computer, args) -> context.executeMainThreadTask(() -> ResultHelpers.checkNormalResult(m.apply(target, context, computer, args.escapes())))
+        m -> (target, context, computer, args) -> {
+            var escArgs = args.escapes();
+            return context.executeMainThreadTask(() -> ResultHelpers.checkNormalResult(m.apply(target, context, computer, escArgs)));
+        }
     );
     private static final IntCache<PeripheralMethod> DYNAMIC = new IntCache<>(
         method -> (instance, context, computer, args) -> ((IDynamicPeripheral) instance).callMethod(computer, context, method, args)
diff --git a/projects/core/src/main/java/dan200/computercraft/core/lua/VarargArguments.java b/projects/core/src/main/java/dan200/computercraft/core/lua/VarargArguments.java
index 4289d2919..51b71de8c 100644
--- a/projects/core/src/main/java/dan200/computercraft/core/lua/VarargArguments.java
+++ b/projects/core/src/main/java/dan200/computercraft/core/lua/VarargArguments.java
@@ -191,6 +191,7 @@ public Optional<ByteBuffer> optBytes(int index) throws LuaException {
     @Override
     public IArguments escapes() {
         if (escapes) return this;
+        if (isClosed()) throw new IllegalStateException("Cannot call escapes after IArguments has been closed.");
 
         var cache = this.cache;
         var typeNames = this.typeNames;
diff --git a/projects/core/src/test/java/dan200/computercraft/core/lua/VarargArgumentsTest.java b/projects/core/src/test/java/dan200/computercraft/core/lua/VarargArgumentsTest.java
index 7a76ea562..97a6aa36c 100644
--- a/projects/core/src/test/java/dan200/computercraft/core/lua/VarargArgumentsTest.java
+++ b/projects/core/src/test/java/dan200/computercraft/core/lua/VarargArgumentsTest.java
@@ -60,4 +60,12 @@ public void testGetAfterClose() {
         assertThrows(IllegalStateException.class, () -> args.get(0));
         assertThrows(IllegalStateException.class, () -> args.getType(0));
     }
+
+    @Test
+    public void testEscapeAfterClose() {
+        var args = VarargArguments.of(tableWithCustomType());
+        args.close();
+
+        assertThrows(IllegalStateException.class, args::escapes);
+    }
 }