diff --git a/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java b/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java
index 18737a1da..3b6e08e5d 100644
--- a/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java
+++ b/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java
@@ -822,7 +822,7 @@ public class SimpleFunctionRegistry implements FunctionRegistry, FunctionInspect
 					convertedValue = value;
 				}
 				if (value instanceof Message<?>) { // see AWS adapter with Optional payload
-					if (messageNeedsConversion(rawType, (Message<?>) value)) {
+					if (messageNeedsConversion(rawType, type, (Message<?>) value)) {
 
 						boolean convertWithHint = false;
 						Type hint = type;
@@ -956,13 +956,24 @@ public class SimpleFunctionRegistry implements FunctionRegistry, FunctionInspect
 			return false;
 		}
 
-		private boolean messageNeedsConversion(Type rawType, Message<?> message) {
+		private boolean messageNeedsConversion(Type rawType, Type type, Message<?> message) {
 			Boolean skipConversion = message.getHeaders().containsKey(FunctionProperties.SKIP_CONVERSION_HEADER)
 				? message.getHeaders().get(FunctionProperties.SKIP_CONVERSION_HEADER, Boolean.class)
 				: false;
 			if (skipConversion) {
 				return false;
 			}
+
+			if (FunctionTypeUtils.isTypeCollection(message.getPayload().getClass())
+					&& !CollectionUtils.isEmpty((Collection<?>) message.getPayload())) {
+
+				Class<?> elementType = CollectionUtils.findCommonElementType((Collection<?>) message.getPayload());
+				Class<?> itemType = TypeResolver.resolveRawClass(FunctionTypeUtils.getImmediateGenericType(type, 0), null);
+				if (elementType == itemType) {
+					return false;
+				}
+			}
+
 			return rawType instanceof Class<?>
 				&& !(message.getPayload() instanceof Optional)
 				&& !this.payloadIsSpecialType(message.getPayload())
diff --git a/spring-cloud-function-context/src/test/java/org/springframework/cloud/function/userissues/UserIssuesTests.java b/spring-cloud-function-context/src/test/java/org/springframework/cloud/function/userissues/UserIssuesTests.java
index 75ba98c11..544a91558 100644
--- a/spring-cloud-function-context/src/test/java/org/springframework/cloud/function/userissues/UserIssuesTests.java
+++ b/spring-cloud-function-context/src/test/java/org/springframework/cloud/function/userissues/UserIssuesTests.java
@@ -17,14 +17,17 @@
 package org.springframework.cloud.function.userissues;
 
 import java.lang.reflect.Type;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.function.Function;
 
 import org.junit.Before;
 import org.junit.Test;
+
 import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.cloud.function.context.FunctionCatalog;
+import org.springframework.cloud.function.context.catalog.FunctionTypeUtils;
 import org.springframework.cloud.function.json.JsonMapper;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
@@ -61,6 +64,37 @@ public class UserIssuesTests {
 		int result = function.apply(
 				new GenericMessage<String>("[{\"name\":\"julien\"},{\"name\":\"ricky\"},{\"name\":\"bubbles\"}]"));
 		assertThat(result).isEqualTo(3);
+	}
+
+	@Test
+	public void testIssue602asPOJO() throws Exception {
+		FunctionCatalog catalog = this.configureCatalog(Issue602Configuration.class);
+		Function<Message<List<Product>>, Integer> function = catalog.lookup("consumer");
+		ArrayList<Product> products = new ArrayList<>();
+		Product p = new Product();
+		p.setName("julien");
+		products.add(p);
+		p = new Product();
+		p.setName("ricky");
+		products.add(p);
+		p = new Product();
+		p.setName("bubbles");
+		products.add(p);
+		int result = function.apply(new GenericMessage<List<Product>>(products));
+		assertThat(result).isEqualTo(3);
+
+	}
+
+	@Test
+	public void testIssue602asCollectionOfUnconvertedItems() throws Exception {
+		FunctionCatalog catalog = this.configureCatalog(Issue602Configuration.class);
+		Function<Message<List<String>>, Integer> function = catalog.lookup("consumer");
+		ArrayList<String> products = new ArrayList<>();
+		products.add("{\"name\":\"julien\"}");
+		products.add("{\"name\":\"ricky\"}");
+		products.add("{\"name\":\"bubbles\"}");
+		int result = function.apply(new GenericMessage<List<String>>(products));
+		assertThat(result).isEqualTo(3);
 
 	}
 
@@ -105,6 +139,9 @@ public class UserIssuesTests {
 
 		@Override
 		protected boolean canConvertFrom(Message<?> message, Class<?> targetClass) {
+			if (!FunctionTypeUtils.isTypeCollection(message.getPayload().getClass())) {
+				return false;
+			}
 			return true;
 		}