diff --git a/Tusker/LazilyDecoding.swift b/Tusker/LazilyDecoding.swift
index c77eed6b..542f1d3c 100644
--- a/Tusker/LazilyDecoding.swift
+++ b/Tusker/LazilyDecoding.swift
@@ -11,13 +11,13 @@ import Foundation
 private let decoder = PropertyListDecoder()
 private let encoder = PropertyListEncoder()
 
-// todo: invalidate cache on underlying data change using KVO?
 @propertyWrapper
-public struct LazilyDecoding<Enclosing, Value: Codable> {
+public struct LazilyDecoding<Enclosing: NSObject, Value: Codable> {
 
     private let keyPath: ReferenceWritableKeyPath<Enclosing, Data?>
     private let fallback: Value
     private var value: Value?
+    private var observation: NSKeyValueObservation?
     
     init(from keyPath: ReferenceWritableKeyPath<Enclosing, Data?>, fallback: Value) {
         self.keyPath = keyPath
@@ -39,6 +39,12 @@ public struct LazilyDecoding<Enclosing, Value: Codable> {
                 do {
                     let value = try decoder.decode(Box<Value>.self, from: data)
                     wrapper.value = value.value
+                    wrapper.observation = instance.observe(wrapper.keyPath, changeHandler: { instance, _ in
+                        var updated = instance[keyPath: storageKeyPath]
+                        updated.value = nil
+                        updated.observation = nil
+                        instance[keyPath: storageKeyPath] = updated
+                    })
                     instance[keyPath: storageKeyPath] = wrapper
                     return value.value
                 } catch {