Question Can't load an atlased sprite (everything else loads fine)

At a loss here. I must be missing some basic info.

Code (CSharp):

1.  public class MyApp : MonoBehaviour
2. {
3.         // Set to proper values in the editor
4.    
5.         public AssetReferenceSprite NonAtlased;
6.         public AssetReferenceSprite AtlasedSprite;
7.  
8.         void Awake()
9.         {
10.             Invoke("StartTest", 0.1f);
11.         }
12.  
13.         public void StartTest()
14.         {
15.             // Load atlas and load non-atlased sprites work fine
16.        
17.             Addressables.LoadAssetAsync<SpriteAtlas>("TestAtlas").Completed += OnAtlasLoaded;
18.             NonAtlased.LoadAssetAsync().Completed += OnSpriteLoaded;
19.  
20.             // Any atlas sprite loading fails, even if called after the atlas is loaded
21.  
22.             Addressables.LoadAssetAsync<Sprite>("TestAtlas[TestHeart]").Completed += OnSpriteLoaded;
23.             AtlasedSprite.LoadAssetAsync().Completed += OnSpriteLoaded;
24.  

I get the following for atlased sprites:

Exception encountered in operation UnityEngine.ResourceManagement.ResourceManager+CompletedOperation`1[UnityEngine.Sprite], result='', status='Failed': Exception of type 'UnityEngine.AddressableAssets.InvalidKeyException' was thrown., Key=, Type=UnityEngine.Sprite
Exception encountered in operation UnityEngine.AddressableAssets.Initialization.InitializationOperation, result='', status='Succeeded' - Chain<Sprite>: ChainOperation of Type: UnityEngine.Sprite failed because dependent operation failed

Any ideas? Is there a manual "build atlases" step I'm missing?

 

This appears fixed in 1.10 (although I can't get data to appear in my event viewer now).