diff --git a/src/Packages/Audience/Runtime/AudienceConfig.cs b/src/Packages/Audience/Runtime/AudienceConfig.cs
index c4b2ae9af..deda29847 100644
--- a/src/Packages/Audience/Runtime/AudienceConfig.cs
+++ b/src/Packages/Audience/Runtime/AudienceConfig.cs
@@ -40,5 +40,11 @@ public class AudienceConfig
 
         // Test seam for HttpTransport; not part of the public API.
         internal System.Net.Http.HttpMessageHandler? HttpHandler { get; set; }
+
+        // Makes a shallow copy so Init can fill in PersistentDataPath without
+        // modifying the caller's object. Delegates and handlers (OnError,
+        // HttpHandler) are deliberately kept as the same instance — cloning
+        // them would break their behaviour.
+        internal AudienceConfig Clone() => (AudienceConfig)MemberwiseClone();
     }
 }
diff --git a/src/Packages/Audience/Runtime/ImmutableAudience.cs b/src/Packages/Audience/Runtime/ImmutableAudience.cs
index e90ef7b46..c35c08e5b 100644
--- a/src/Packages/Audience/Runtime/ImmutableAudience.cs
+++ b/src/Packages/Audience/Runtime/ImmutableAudience.cs
@@ -47,9 +47,14 @@ public static class ImmutableAudience
         public static void Init(AudienceConfig config)
         {
             if (config == null) throw new ArgumentNullException(nameof(config));
+
+            // Copy the caller's config so filling in PersistentDataPath below
+            // doesn't change the object they passed in. Validating after the
+            // clone keeps the compiler's null-flow analysis for PublishableKey
+            // alive through the HttpTransport constructor below.
+            config = config.Clone();
             if (string.IsNullOrEmpty(config.PublishableKey))
                 throw new ArgumentException("PublishableKey is required", nameof(config));
-
             if (string.IsNullOrEmpty(config.PersistentDataPath))
                 config.PersistentDataPath = DefaultPersistentDataPathProvider?.Invoke();
             if (string.IsNullOrEmpty(config.PersistentDataPath))