diff --git a/spring-cloud-function-rsocket/src/main/java/org/springframework/cloud/function/rsocket/FunctionRSocketMessageHandler.java b/spring-cloud-function-rsocket/src/main/java/org/springframework/cloud/function/rsocket/FunctionRSocketMessageHandler.java
index 2507c9921..a61e006f0 100644
--- a/spring-cloud-function-rsocket/src/main/java/org/springframework/cloud/function/rsocket/FunctionRSocketMessageHandler.java
+++ b/spring-cloud-function-rsocket/src/main/java/org/springframework/cloud/function/rsocket/FunctionRSocketMessageHandler.java
@@ -248,24 +248,17 @@ class FunctionRSocketMessageHandler extends RSocketMessageHandler {
 					? Flux.just((DataBuffer) payload)
 							: Flux.from((Publisher<DataBuffer>) payload);
 
-			if (MimeTypeUtils.APPLICATION_JSON_VALUE.equals(message.getHeaders().get(MessageHeaders.CONTENT_TYPE).toString())) {
+			if (message.getHeaders().containsKey(MessageHeaders.CONTENT_TYPE)
+					&& MimeTypeUtils.APPLICATION_JSON_VALUE.equals(message.getHeaders().get(MessageHeaders.CONTENT_TYPE).toString())) {
 				Flux<Object> argument = data.map(buffer -> {
 					byte[] bytePayload = this.decoder.decode(buffer, ResolvableType.forType(byte[].class), null, null);
 					if (JsonMapper.isJsonString(bytePayload)) {
 //						// could be array, map or string
 						Object structure = this.jsonMapper.fromJson(bytePayload, Object.class);
-						if (structure instanceof Map) {
-							if (((Map<String, ?>) structure).containsKey(FunctionRSocketUtils.PAYLOAD)) {
-								return MessageBuilder.withPayload(((Map<String, ?>) structure).remove(FunctionRSocketUtils.PAYLOAD))
-										.copyHeaders((Map<String, ?>) ((Map<String, ?>) structure).get(FunctionRSocketUtils.HEADERS))
-										.build();
-							}
-							else {
-								return MessageBuilder.withPayload(structure).build();
-							}
-						}
-						else {
-							return MessageBuilder.withPayload(structure).build();
+						if (structure instanceof Map && ((Map<String, ?>) structure).containsKey(FunctionRSocketUtils.PAYLOAD)) {
+							return MessageBuilder.withPayload(((Map<String, ?>) structure).remove(FunctionRSocketUtils.PAYLOAD))
+									.copyHeaders((Map<String, ?>) ((Map<String, ?>) structure).get(FunctionRSocketUtils.HEADERS))
+									.build();
 						}
 					}
 					return MessageBuilder.withPayload(bytePayload).copyHeadersIfAbsent(message.getHeaders()).build();