diff --git a/system/src/Grav/Common/Assets.php b/system/src/Grav/Common/Assets.php
index cd00e1b16..9c270d986 100644
--- a/system/src/Grav/Common/Assets.php
+++ b/system/src/Grav/Common/Assets.php
@@ -269,7 +269,12 @@ class Assets extends PropertyObject
 
         // Add timestamp
         $timestamp_override = $options['timestamp'] ?? true;
-        $options['timestamp'] = $this->timestamp && filter_var($timestamp_override, FILTER_VALIDATE_BOOLEAN);
+
+        if (filter_var($timestamp_override, FILTER_VALIDATE_BOOLEAN)) {
+            $options['timestamp'] = $this->timestamp;
+        } else {
+            $options['timestamp'] = null;
+        }
 
         // Set order
         $group = $options['group'] ?? 'head';