diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index d3ef77696ce..889c22f68ca 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -579,7 +579,9 @@ impl Node {
                 return;
             }
 
-            ancestor.set_flag(NodeFlags::HAS_DIRTY_DESCENDANTS, true);
+            if ancestor.is::<Element>() {
+                ancestor.set_flag(NodeFlags::HAS_DIRTY_DESCENDANTS, true);
+            }
         }
     }