diff --git a/roaring/containers_btree.go b/roaring/containers_btree.go
index 72837dcb4..c31f0d746 100644
--- a/roaring/containers_btree.go
+++ b/roaring/containers_btree.go
@@ -189,6 +189,8 @@ func (btc *bTreeContainers) Repair() {
 // replace the given container.
 func (btc *bTreeContainers) Update(key uint64, fn func(*Container, bool) (*Container, bool)) {
 	btc.tree.Put(key, fn)
+	btc.lastKey = ^uint64(0)
+	btc.lastContainer = nil
 }
 
 // UpdateEvery calls fn (existing-container, existed), and expects
diff --git a/roaring/containers_slice.go b/roaring/containers_slice.go
index 79798adb0..8597b0f8d 100644
--- a/roaring/containers_slice.go
+++ b/roaring/containers_slice.go
@@ -210,6 +210,7 @@ func (sc *sliceContainers) Update(key uint64, fn func(*Container, bool) (*Contai
 			sc.insertAt(key, nc, i)
 		}
 	}
+	sc.invalidateCache()
 }
 
 // UpdateEvery calls fn (existing-container, existed), and expects