IAP Crash

I am getting thousands of reports on the services dashboard for this error:
Unity 2018.3.0f1, Gameroom build.
Has happened in every version from 2017, its not new to 2018.3.
Latest version of IAP plugin, but again not new to this, its always happened. I've just got fed up of seeing it..

Code (CSharp):

1. NullReferenceException: Object reference not set to an instance of an object
2.  
3. Managed Stack Trace:
4.  
5. UnityEngine.Purchasing.JSONSerializer.DeserializeProductDescriptions (System.String json) (at <503e163f382c423ab7d75e3b1cb99f4f>:0)
6. UnityEngine.Purchasing.JSONStore.OnProductsRetrieved (System.String json) (at <503e163f382c423ab7d75e3b1cb99f4f>:0)
7. UnityEngine.Purchasing.FacebookStoreImpl.ProcessMessage (System.String subject, System.String payload, System.String receipt, System.String transactionId) (at <503e163f382c423ab7d75e3b1cb99f4f>:0)
8. UnityEngine.Purchasing.FacebookStoreImpl+<>c__DisplayClass6_0.<MessageCallback>b__0 () (at <503e163f382c423ab7d75e3b1cb99f4f>:0)
9. UnityEngine.Purchasing.Extension.UnityUtil.Update () (at <503e163f382c423ab7d75e3b1cb99f4f>:0)

Also this:

Code (CSharp):

1. ArgumentException: An item with the same key has already been added. Key: ...
2.  
3. Managed Stack Trace:
4.  
5. System.Collections.Generic.Dictionary`2[TKey,TValue].TryInsert (TKey key, TValue value, System.Collections.Generic.InsertionBehavior behavior) (at <0000d56de0ae43ca875d7babfd990580>:0)
6. System.Collections.Generic.Dictionary`2[TKey,TValue].Add (TKey key, TValue value) (at <0000d56de0ae43ca875d7babfd990580>:0)
7. UnityEngine.Purchasing.FacebookStoreBindings.ProductListCallback (Facebook.Unity.IGraphResult result) (at <d47ac846118441d2852aa05247f414f8>:0)
8. Facebook.Unity.AsyncRequestString+<Start>d__9.MoveNext () (at <73a87e4086d24d19bbdbcee40c7995d3>:0)
9. UnityEngine.SetupCoroutine.InvokeMoveNext (System.Collections.IEnumerator enumerator, System.IntPtr returnValueAddress) (at <9b3b6573bfb64614aa7ee01c0905dc79>:0)

 

It's probably from advantage, if you could you submit a bug-report, as described in this document:
https://unity3d.com/unity/qa/bug-reporting

After you submitted the bug-report, you receive a confirmation email with a bug-report Case number. You can post this Case number here (in this forum thread) for Unity staff to pick up, in case they see this post.