diff --git a/packages/node_modules/@node-red/nodes/core/network/10-mqtt.js b/packages/node_modules/@node-red/nodes/core/network/10-mqtt.js
index 4e47b17f1..5d4efaf93 100644
--- a/packages/node_modules/@node-red/nodes/core/network/10-mqtt.js
+++ b/packages/node_modules/@node-red/nodes/core/network/10-mqtt.js
@@ -1040,7 +1040,7 @@ module.exports = function(RED) {
 
                             //subscribe to sub.topic & hook up subscriptionHandler
                             node.brokerConn.subscribe(sub.topic, options, function (topic, payload, packet) {
-                                subscriptionHandler(node, sub.datatype, topic, payload, packet);
+                                subscriptionHandler(node, sub.datatype || node.datatype, topic, payload, packet);
                             }, node.id);
                             node.dynamicSubs[sub.topic] = sub; //save for later unsubscription & 'list' action
                         })