--- a/layout/base/ServoRestyleManager.cpp
+++ b/layout/base/ServoRestyleManager.cpp
@@ -1164,16 +1164,20 @@ ServoRestyleManager::TakeSnapshotForAttr
   }
 
   // We cannot tell if the attribute change will affect the styles of
   // undisplayed elements, because we don't actually restyle those elements
   // during the restyle traversal. So just assume that the attribute change can
   // cause the style to change.
   IncrementUndisplayedRestyleGeneration();
 
+  // Some other random attribute changes may also affect the transitions,
+  // so we also set this true here.
+  mHaveNonAnimationRestyles = true;
+
   ServoElementSnapshot& snapshot = SnapshotFor(aElement);
   snapshot.AddAttrs(aElement, aNameSpaceID, aAttribute);
 
   if (influencesOtherPseudoClassState) {
     snapshot.AddOtherPseudoClassState(aElement);
   }
 
   if (Element* parent = aElement->GetFlattenedTreeParentElementForStyle()) {
@@ -1223,16 +1227,20 @@ ServoRestyleManager::AttributeChanged(El
   if (restyleHint || changeHint) {
     Servo_NoteExplicitHints(aElement, restyleHint, changeHint);
   }
 
   if (restyleHint) {
     // Assuming we need to invalidate cached style in getComputedStyle for
     // undisplayed elements, since we don't know if it is needed.
     IncrementUndisplayedRestyleGeneration();
+
+    // If we change attributes, we have to mark this to be true, so we will
+    // increase the animation generation for the new created transition if any.
+    mHaveNonAnimationRestyles = true;
   }
 }
 
 nsresult
 ServoRestyleManager::ReparentStyleContext(nsIFrame* aFrame)
 {
   // This is only called when moving frames in or out of the first-line
   // pseudo-element (or one of its inline descendants).  So aFrame's ancestors