diff --git a/runtime/src/main/java/dev/cel/runtime/CelRuntimeLegacyImpl.java b/runtime/src/main/java/dev/cel/runtime/CelRuntimeLegacyImpl.java
index f5f96e5c..81beec7c 100644
--- a/runtime/src/main/java/dev/cel/runtime/CelRuntimeLegacyImpl.java
+++ b/runtime/src/main/java/dev/cel/runtime/CelRuntimeLegacyImpl.java
@@ -266,7 +266,9 @@ public CelRuntimeLegacyImpl build() {
       }
 
       return new CelRuntimeLegacyImpl(
-          new DefaultInterpreter(runtimeTypeProvider, dispatcher, options), options, this);
+          new DefaultInterpreter(runtimeTypeProvider, dispatcher.immutableCopy(), options),
+          options,
+          this);
     }
 
     private static CelDescriptorPool newDescriptorPool(