Bug Generic systems with SystemAPI.Query returns null component

Happened when upgrading Entities from experimental to pre release package 1.0.0-pre.15.

Code (CSharp):

1. using Unity.Entities;
2.  
3. public struct TestComponent : IComponentData
4. {
5.     public byte value;
6. }
7.  
8. public abstract partial class GenericWrite<C> : SystemBase where C : struct, IComponentData
9. {
10.     protected override void OnUpdate()
11.     {
12.         foreach (var settingsData in SystemAPI.Query<RefRW<C>>())
13.         {
14.             var data = new C();
15.             settingsData.ValueRW = data;
16.         }
17.     }
18. }
19.  
20. public abstract partial class GenericRead<C> : SystemBase where C : struct, IComponentData
21. {
22.     protected override void OnUpdate()
23.     {
24.         foreach (var settingsData in SystemAPI.Query<RefRO<C>>())
25.         {
26.             var readData = settingsData.ValueRO;
27.         }
28.     }
29. }
30.  
31. public partial class InitializeClientSettingsSingletonSystem : SystemBase
32. {
33.     protected override void OnUpdate()
34.     {
35.         var newEnt = EntityManager.CreateEntity();
36.         EntityManager.AddComponentData(newEnt, new TestComponent());
37.         this.Enabled = false;
38.     }
39. }
40.  
41. public class WriteSystem : GenericWrite<TestComponent> { }
42.  
43.  
44. public class ReadSystem : GenericRead<TestComponent> { }
45.  

Spoiler: Error

NullReferenceException: Object reference not set to an instance of an object
Unity.Collections.LowLevel.Unsafe.AtomicSafetyHandle.CheckReadAndThrow (Unity.Collections.LowLevel.Unsafe.AtomicSafetyHandle handle) (at <44569b2d1c974b5eb5e85c3450cfe46d>:0)
Unity.Entities.RefRO`1[T].get_ValueRO () (at Library/PackageCache/com.unity.entities@1.0.0-pre.15/Unity.Entities/Iterators/RefRO.cs:86)
GenericRead`1[C].OnUpdate () (at Assets/Scripts/GenericSystemTest.cs:26)
Unity.Entities.SystemBase.Update () (at Library/PackageCache/com.unity.entities@1.0.0-pre.15/Unity.Entities/SystemBase.cs:428)
Unity.Entities.ComponentSystemGroup.UpdateAllSystems () (at Library/PackageCache/com.unity.entities@1.0.0-pre.15/Unity.Entities/ComponentSystemGroup.cs:670)
UnityEngine.Debug:LogException(Exception)

CASE IN-26346

Hope it gets fixed soon ^^