To reproduce:
1. Open attached project
2. Press play in the editor
3. Check the console for errors

Actual results: NullReferenceException appears after entering play mode
Expected results: There should be no errors

Reproduced with: 2018.4.10f1; 2020.1.0a7

Errors:
NullReferenceException: Object reference not set to an instance of an object
CustomizationController+<>c.<Start>b__9_0 (UnityEngine.ResourceManagement.AsyncOperations.AsyncOperationHandle`1[TObject] op) (at Assets/Scripts/CustomizationController.cs:36)
DelegateList`1[T].Invoke (T res) (at Library/PackageCache/com.unity.addressables@1.2.2/Runtime/ResourceManager/Util/DelegateList.cs:69)
UnityEngine.Debug:LogException(Exception)
DelegateList`1:Invoke(AsyncOperationHandle`1) (at Library/PackageCache/com.unity.addressables@1.2.2/Runtime/ResourceManager/Util/DelegateList.cs:73)
UnityEngine.ResourceManagement.ResourceManager:Update(Single)
MonoBehaviourCallbackHooks:Update() (at Library/PackageCache/com.unity.addressables@1.2.2/Runtime/ResourceManager/Util/MonoBehaviourCallbackHooks.cs:19)

Exception encountered in operation UnityEngine.AddressableAssets.Initialization.InitializationOperation, result='', status='Succeeded' - Chain<DataScriptableObject,IResourceLocator>: ChainOperation of Type: DataScriptableObject failed because dependent operation failed
Unknown error in AsyncOperation
UnityEngine.ResourceManagement.ChainOperation`2:OnWrappedCompleted(AsyncOperationHandle`1)
DelegateList`1:Invoke(AsyncOperationHandle`1) (at Library/PackageCache/com.unity.addressables@1.2.2/Runtime/ResourceManager/Util/DelegateList.cs:69)
UnityEngine.ResourceManagement.ResourceManager:Update(Single)
MonoBehaviourCallbackHooks:Update() (at Library/PackageCache/com.unity.addressables@1.2.2/Runtime/ResourceManager/Util/MonoBehaviourCallbackHooks.cs:19)

Exception encountered in operation Resource<DataScriptableObject>(DataObject.asset): Unknown error in AsyncOperation
UnityEngine.AsyncOperation:InvokeCompletionEvent()