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 f6107915d..67e3cb8c6 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
@@ -1325,6 +1325,9 @@ public class SimpleFunctionRegistry implements FunctionRegistry, FunctionInspect
 					? SimpleFunctionRegistry.this.messageConverter.fromMessage(message, rawType, itemType)
 					: SimpleFunctionRegistry.this.messageConverter.fromMessage(message, rawType);
 
+			if (convertedInput != null && !rawType.isAssignableFrom(convertedInput.getClass())) {
+				logger.warn("Failed to convert input to " + rawType + ". Will attempt to invoke function with raw type");
+			}
 
 			if (FunctionTypeUtils.isMessage(type)) {
 				if (convertedInput == null) {
diff --git a/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/config/SmartCompositeMessageConverter.java b/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/config/SmartCompositeMessageConverter.java
index da17b2641..0c32f8c9d 100644
--- a/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/config/SmartCompositeMessageConverter.java
+++ b/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/config/SmartCompositeMessageConverter.java
@@ -66,8 +66,8 @@ public class SmartCompositeMessageConverter extends CompositeMessageConverter {
 				}
 			}
 			catch (Exception e) {
-				if (logger.isDebugEnabled()) {
-					logger.debug("Failure during type conversion by " + converter + ". Will try the next converter.", e);
+				if (logger.isWarnEnabled()) {
+					logger.warn("Failure during type conversion by " + converter + ". Will try the next converter.", e);
 				}
 			}
 		}