diff --git a/pkg/eventfilter/subscriptionsapi/not_filter.go b/pkg/eventfilter/subscriptionsapi/not_filter.go
index 9f64421b488..57d98ae0391 100644
--- a/pkg/eventfilter/subscriptionsapi/not_filter.go
+++ b/pkg/eventfilter/subscriptionsapi/not_filter.go
@@ -48,6 +48,8 @@ func (filter *notFilter) Filter(ctx context.Context, event cloudevents.Event) ev
 	return eventfilter.NoFilter
 }
 
-func (filter *notFilter) Cleanup() {}
+func (filter *notFilter) Cleanup() {
+	filter.filter.Cleanup()
+}
 
 var _ eventfilter.Filter = &notFilter{}