diff --git a/afterburner/src/main/java/tools/jackson/module/afterburner/deser/ABDeserializerModifier.java b/afterburner/src/main/java/tools/jackson/module/afterburner/deser/ABDeserializerModifier.java
index ef77b6c3..65413098 100644
--- a/afterburner/src/main/java/tools/jackson/module/afterburner/deser/ABDeserializerModifier.java
+++ b/afterburner/src/main/java/tools/jackson/module/afterburner/deser/ABDeserializerModifier.java
@@ -46,7 +46,7 @@ public BeanDeserializerBuilder updateBuilder(DeserializationConfig config,
         // [module-afterburner#21]: Can't force access to sealed packages, or anything within "java."
         if (!MyClassLoader.canAddClassInPackageOf(beanClass)) {
             return builder;
-        } 
+        }
         /* Hmmh. Can we access stuff from private classes?
          * Possibly, if we can use parent class loader.
          * (should probably skip all non-public?)
diff --git a/afterburner/src/main/java/tools/jackson/module/afterburner/deser/SuperSonicBeanDeserializer.java b/afterburner/src/main/java/tools/jackson/module/afterburner/deser/SuperSonicBeanDeserializer.java
index 00394509..d33870cf 100644
--- a/afterburner/src/main/java/tools/jackson/module/afterburner/deser/SuperSonicBeanDeserializer.java
+++ b/afterburner/src/main/java/tools/jackson/module/afterburner/deser/SuperSonicBeanDeserializer.java
@@ -332,7 +332,8 @@ public Object deserializeFromObject(JsonParser p, DeserializationContext ctxt)
         }
         // also, need to ensure we get closing END_OBJECT...
         if (p.nextToken() != JsonToken.END_OBJECT) {
-            return _handleUnexpectedWithin(p, ctxt, bean);
+            // [modules-base#343]: trailing (possibly unknown) properties remain
+            return _deserializeDisordered(p, ctxt, bean);
         }
         return bean;
     }
diff --git a/release-notes/VERSION b/release-notes/VERSION
index 772c6fd4..1a24c16d 100644
--- a/release-notes/VERSION
+++ b/release-notes/VERSION
@@ -26,6 +26,13 @@ Active maintainers:
 
 No changes since 3.1
 
+3.1.3 (not yet released)
+
+#343: Deserialization Failed when an unknown property is added in JSON
+  when using Afterburner Module
+ (reported by @leowongkh)
+ (fix by @cowtowncoder, w/ Claude code)
+
 3.1.2 (11-Apr-2026)
 3.1.1 (27-Mar-2026)