--- a/layout/style/ServoBindings.cpp
+++ b/layout/style/ServoBindings.cpp
@@ -536,20 +536,32 @@ Gecko_UpdateAnimations(RawGeckoElementBo
     if (aTasks & UpdateAnimationsTasks::CSSTransitions) {
       MOZ_ASSERT(aOldComputedValues);
       const ServoComputedValuesWithParent oldServoValues =
         { aOldComputedValues, nullptr };
       presContext->TransitionManager()->
         UpdateTransitions(const_cast<dom::Element*>(aElement), pseudoType,
                           oldServoValues, servoValues);
     }
+
     if (aTasks & UpdateAnimationsTasks::EffectProperties) {
       presContext->EffectCompositor()->UpdateEffectProperties(
         servoValues, const_cast<dom::Element*>(aElement), pseudoType);
     }
+
+    if (aTasks & UpdateAnimationsTasks::CascadeResults) {
+      // This task will be scheduled if we detected any changes to !important
+      // rules. We post a restyle here so that we can update the cascade
+      // results in the pre-traversal of the next restyle.
+      presContext->EffectCompositor()
+                 ->RequestRestyle(const_cast<Element*>(aElement),
+                                  pseudoType,
+                                  EffectCompositor::RestyleType::Standard,
+                                  EffectCompositor::CascadeLevel::Animations);
+    }
   }
 }
 
 bool
 Gecko_ElementHasAnimations(RawGeckoElementBorrowed aElement)
 {
   nsIAtom* pseudoTag = PseudoTagAndCorrectElementForAnimation(aElement);
   CSSPseudoElementType pseudoType =