diff --git a/app/Controller/WorkflowsController.php b/app/Controller/WorkflowsController.php
index b935bfee4..d432357b0 100644
--- a/app/Controller/WorkflowsController.php
+++ b/app/Controller/WorkflowsController.php
@@ -172,6 +172,12 @@ class WorkflowsController extends AppController
     {
         if ($this->request->is('post') || $this->request->is('put')) {
             $blockingErrors = [];
+            if (!JsonTool::isValid($this->request->data['Workflow']['data'])) {
+                return $this->RestResponse->viewData([
+                    'success' => false,
+                    'outcome' => __('Invalid JSON'),
+                ], $this->response->type());
+            }
             $data = JsonTool::decode($this->request->data['Workflow']['data']);
             $result = $this->Workflow->executeWorkflow($workflow_id, $data, $blockingErrors);
             if (!empty($logging) && empty($result['success'])) {
diff --git a/app/Model/Workflow.php b/app/Model/Workflow.php
index b75e52661..042550d56 100644
--- a/app/Model/Workflow.php
+++ b/app/Model/Workflow.php
@@ -522,7 +522,25 @@ class Workflow extends AppModel
         $workflow = $this->__incrementWorkflowExecutionCount($workflow);
         $walkResult = [];
         $debugData = ['original' => $data];
-        $data = $this->__normalizeDataForTrigger($triggerModule, $data);
+        $conversionFailure = false;
+        try {
+            $data = $this->__normalizeDataForTrigger($triggerModule, $data);
+        } catch (Exception $e) {
+            $conversionFailure = true;
+            $message = __('Error while normalizing data for trigger. Error:' . PHP_EOL . $e->getMessage());
+        }
+        if ($data === false) {
+            $conversionFailure = true;
+            $message = __('Error while normalizing data for trigger. Invalid input.');
+        }
+        if ($conversionFailure) {
+            $this->logExecutionIfDebug($workflow, $message);
+            return [
+                'outcomeText' => 'failure' . sprintf(' %s', $message),
+                'walkResult' => [],
+                'success' => false,
+            ];
+        }
         $debugData['normalized'] = $data;
         $for_path = !empty($triggerModule->blocking) ? GraphWalker::PATH_TYPE_BLOCKING : GraphWalker::PATH_TYPE_NON_BLOCKING;
         $this->sendRequestToDebugEndpointIfDebug($workflow, [], '/init?type=' . $for_path, $debugData);
@@ -710,10 +728,10 @@ class Workflow extends AppModel
         return $success;
     }
 
-    private function __normalizeDataForTrigger($triggerClass, array $data): array
+    private function __normalizeDataForTrigger($triggerClass, array $data)
     {
         if (method_exists($triggerClass, 'normalizeData')) {
-            return $triggerClass->normalizeData($data);
+            $data = $triggerClass->normalizeData($data);
         }
         return $data;
     }
diff --git a/app/Model/WorkflowModules/trigger/Module_post_after_save.php b/app/Model/WorkflowModules/trigger/Module_post_after_save.php
index ea00835ce..9b905ca29 100644
--- a/app/Model/WorkflowModules/trigger/Module_post_after_save.php
+++ b/app/Model/WorkflowModules/trigger/Module_post_after_save.php
@@ -23,6 +23,11 @@ class Module_post_after_save extends WorkflowBaseTriggerModule
     public function normalizeData(array $data)
     {
         parent::normalizeData($data);
+
+        if (empty($data['Post'])) {
+            return false;
+        }
+
         $this->Thread = ClassRegistry::init('Thread');
         $thread = $this->Thread->find('first', [
             'recursive' => -1,
diff --git a/app/Model/WorkflowModules/trigger/Module_sighting_after_save.php b/app/Model/WorkflowModules/trigger/Module_sighting_after_save.php
index aa09d7b83..96028632c 100644
--- a/app/Model/WorkflowModules/trigger/Module_sighting_after_save.php
+++ b/app/Model/WorkflowModules/trigger/Module_sighting_after_save.php
@@ -26,6 +26,10 @@ class Module_sighting_after_save extends WorkflowBaseTriggerModule
         $this->Event = ClassRegistry::init('Event');
         $this->Attribute = ClassRegistry::init('Attribute');
 
+        if (empty($data['Sighting'])) {
+            return false;
+        }
+
         // We are missing data such as tags or objects.
         $event = $this->Event->quickFetchEvent($data['Sighting']['Event']['id']);
         $attribute = $this->Attribute->fetchAttribute($data['Sighting']['Attribute']['id']);