com.unity.purchasing: 3.1 ArgumentException: An item with the same key has already been added. Key

After Calling builder.AddProduct(string id, ProductType type, IDs storeIDs) with a bunch of products (with different ids) I get this exception (also with version 3.2) when I call UnityPurchasing.Initialize(this, builder);

Code (CSharp):

1. ArgumentException: An item with the same key has already been added. Key:
2.   at System.Collections.Generic.Dictionary`2[TKey,TValue].TryInsert (TKey key, TValue value, System.Collections.Generic.InsertionBehavior behavior) [0x00000] in <00000000000000000000000000000000>:0
3.   at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement] (System.Collections.Generic.IEnumerable`1[T] source, System.Func`2[T,TResult] keySelector, System.Func`2[T,TResult] elementSelector, System.Collections.Generic.IEqualityComparer`1[T] comparer) [0x00000] in <00000000000000000000000000000000>:0
4.   at UnityEngine.Purchasing.ProductCollection.AddProducts (System.Collections.Generic.IEnumerable`1[T] products) [0x00000] in <00000000000000000000000000000000>:0
5.   at UnityEngine.Purchasing.PurchasingManager.Initialize (UnityEngine.Purchasing.IInternalStoreListener listener, System.Collections.Generic.HashSet`1[T] products) [0x00000] in <00000000000000000000000000000000>:0
6.   at System.Action`1[T].Invoke (T obj) [0x00000] in <00000000000000000000000000000000>:0

I'm using Unity version 2020.3.11f1 and the same code I was using before I upgraded from unity Iap 2

Any ideas what could be causing this? I don't see any place where I'm adding a duplicate key
I see this happening on IOS right now but I'm pretty sure also on Android I'll check that soon
TIA

 

The store id was "" and because ProductColection has a Dictionary by storeId in it it was throwing this exception