diff --git a/lib/Application/Attributes/AttributeService.php b/lib/Application/Attributes/AttributeService.php
index 73114e542..31fbe4322 100644
--- a/lib/Application/Attributes/AttributeService.php
+++ b/lib/Application/Attributes/AttributeService.php
@@ -175,6 +175,10 @@ public function Validate($category, $attributeValues, $entityIds = [], $ignoreEm
                 continue;
             }
 
+            if (!$attribute->Required() && !array_key_exists($attribute->Id(), $values)) {
+                continue;
+            }
+
             $value = trim($values[$attribute->Id()]);
             $label = $attribute->Label();