diff --git a/x-pack/legacy/plugins/watcher/public/np_ready/application/models/action/logging_action.js b/x-pack/legacy/plugins/watcher/public/np_ready/application/models/action/logging_action.js
index bef094b57cc8e..1590ee62e68b4 100644
--- a/x-pack/legacy/plugins/watcher/public/np_ready/application/models/action/logging_action.js
+++ b/x-pack/legacy/plugins/watcher/public/np_ready/application/models/action/logging_action.js
@@ -37,7 +37,18 @@ export class LoggingAction extends BaseAction {
 
   get upstreamJson() {
     const result = super.upstreamJson;
-    const text = !!this.text.trim() ? this.text : undefined;
+    let text;
+
+    if (typeof this.text === 'string') {
+      // If this.text is a non-empty string, we can send it to the API.
+      if (!!this.text.trim()) {
+        text = this.text;
+      }
+    } else {
+      // If the user incorrectly defined this.text, e.g. as an object in a JSON watch, let the API
+      // deal with it.
+      text = this.text;
+    }
 
     Object.assign(result, {
       text,