diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
index 96ccd812c4ca..1b2bdbd6b111 100644
--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -1894,6 +1894,7 @@ void Element::UnbindFromTree(bool aNullParent) {
 
   ClearInDocument();
   SetIsConnected(false);
+  ClearElementCreatedFromPrototypeAndHasUnmodifiedL10n();
 
   if (aNullParent || !mParent->IsInShadowTree()) {
     UnsetFlags(NODE_IS_IN_SHADOW_TREE);
@@ -2468,6 +2469,12 @@ nsresult Element::SetAttrAndNotify(
     }
   }
 
+  if (HasElementCreatedFromPrototypeAndHasUnmodifiedL10n() &&
+      aNamespaceID == kNameSpaceID_None &&
+      (aName == nsGkAtoms::datal10nid || aName == nsGkAtoms::datal10nargs)) {
+    ClearElementCreatedFromPrototypeAndHasUnmodifiedL10n();
+  }
+
   CustomElementDefinition* definition = GetCustomElementDefinition();
   // Only custom element which is in `custom` state could get the
   // CustomElementDefinition.
diff --git a/dom/base/nsINode.h b/dom/base/nsINode.h
index 556b28534b92..4643275eb351 100644
--- a/dom/base/nsINode.h
+++ b/dom/base/nsINode.h
@@ -1474,6 +1474,9 @@ class nsINode : public mozilla::dom::EventTarget {
     ElementMayHaveAnonymousChildren,
     // Set if element has CustomElementData.
     ElementHasCustomElementData,
+    // Set if the element was created from prototype cache and
+    // its l10n attributes haven't been changed.
+    ElementCreatedFromPrototypeAndHasUnmodifiedL10n,
     // Guard value
     BooleanFlagCount
   };
@@ -1611,6 +1614,16 @@ class nsINode : public mozilla::dom::EventTarget {
     return GetBoolFlag(ElementHasCustomElementData);
   }
 
+  void SetElementCreatedFromPrototypeAndHasUnmodifiedL10n() {
+    SetBoolFlag(ElementCreatedFromPrototypeAndHasUnmodifiedL10n);
+  }
+  bool HasElementCreatedFromPrototypeAndHasUnmodifiedL10n() {
+    return GetBoolFlag(ElementCreatedFromPrototypeAndHasUnmodifiedL10n);
+  }
+  void ClearElementCreatedFromPrototypeAndHasUnmodifiedL10n() {
+    ClearBoolFlag(ElementCreatedFromPrototypeAndHasUnmodifiedL10n);
+  }
+
  protected:
   void SetParentIsContent(bool aValue) { SetBoolFlag(ParentIsContent, aValue); }
   void SetIsInDocument() { SetBoolFlag(IsInDocument); }
diff --git a/dom/prototype/PrototypeDocumentContentSink.cpp b/dom/prototype/PrototypeDocumentContentSink.cpp
index ff5a24440df5..e9e0da9abd3a 100644
--- a/dom/prototype/PrototypeDocumentContentSink.cpp
+++ b/dom/prototype/PrototypeDocumentContentSink.cpp
@@ -1054,6 +1054,7 @@ nsresult PrototypeDocumentContentSink::CreateElementFromPrototype(
     }
   }
 
+  result->SetElementCreatedFromPrototypeAndHasUnmodifiedL10n();
   result.forget(aResult);
 
   return NS_OK;