diff --git a/app/Customer.php b/app/Customer.php
index a4abf9621..3d1c737d8 100644
--- a/app/Customer.php
+++ b/app/Customer.php
@@ -1013,6 +1013,14 @@ public function setData($data, $replace_data = true, $save = false)
             $result = true;
         } else {
             // Update empty fields.
+            
+            // Do not set last name if first name is already set (and vise versa).
+            if (!empty($this->first_name) && !empty($data['last_name'])) {
+                unset($data['last_name']);
+            }
+            if (!empty($this->last_name) && !empty($data['first_name'])) {
+                unset($data['first_name']);
+            }
             foreach ($data as $key => $value) {
                 if (in_array($key, $this->fillable) && empty($this->$key)) {
                     $this->$key = $value;