Indexing error

Hi,

I'm getting following error when I run the find indexing job.

An exception occurred while indexing content [Link 2269__CatalogContent] [GUID 1706ee5d-d561-42ee-b6f5-d760b59fd968] [Type Product] [Name Duo Green Velvet Allesreiniger]: Value cannot be null.
Parameter name: other
System.ArgumentNullException: Value cannot be null.
Parameter name: other
   at Mediachase.Commerce.Catalog.CatalogKey.CompareTo(CatalogKey other)
   at Mediachase.Commerce.Catalog.CatalogKey.Equals(Object obj)
   at System.Collections.Generic.ObjectEqualityComparer`1.Equals(T x, T y)
   at System.Collections.Generic.List`1.Contains(T item)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.CheckForCircularReference(JsonWriter writer, Object value, JsonProperty property, JsonContract contract, JsonContainerContract containerContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.CalculatePropertyValues(JsonWriter writer, Object value, JsonContainerContract contract, JsonProperty member, JsonProperty property, JsonContract& memberContract, Object& memberValue)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeList(JsonWriter writer, IEnumerable values, JsonArrayContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContainerContract collectionContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize(JsonWriter jsonWriter, Object value, Type objectType)
   at Newtonsoft.Json.Serialization.JsonSerializerProxy.SerializeInternal(JsonWriter jsonWriter, Object value, Type rootType)
   at EPiServer.Find.Api.BulkActionConverter.WriteJson(JsonWriter writer, Object value, JsonSerializer serializer)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeConvertable(JsonWriter writer, JsonConverter converter, Object value, JsonContract contract, JsonContainerContract collectionContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerProperty)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize(JsonWriter jsonWriter, Object value, Type objectType)
   at Newtonsoft.Json.JsonSerializer.SerializeInternal(JsonWriter jsonWriter, Object value, Type objectType)
   at EPiServer.Find.Json.Serializer.SerializeToTextWriter(JsonSerializer serializer, Object value, TextWriter textWriter)
   at EPiServer.Find.Json.Serializer.SerializeObjectsToJsonRequest(JsonSerializer serializer, IJsonRequest jsonRequest, IEnumerable values)
   at EPiServer.Find.Api.BulkCommand.Execute(List`1& serializationFailures)
   at EPiServer.Find.Api.BulkCommand.Execute()
   at EPiServer.Find.Client.Index(IEnumerable objectsToIndex, Boolean deleteLanguageRoutingDuplicatesOnIndex)
   at EPiServer.Find.Cms.ContentIndexer.IndexWithRetry(IContent[] contents, Int32 maxRetries, Boolean deleteLanguageRoutingDuplicatesOnIndex)
   at EPiServer.Find.Cms.ContentIndexer.Index(IEnumerable`1 content, IndexOptions options)
   at EPiServer.Find.Cms.ContentIndexer.IndexBatch(IEnumerable`1 content, Action`1 statusAction, Int32& numberOfContentErrors, Int32& indexingCount, Boolean deleteLanguageRoutingDuplicatesOnIndex)

This is our CatalogContentClientConventions class where we disable variant indexing and include the variants in the product:

    public class SiteCatalogContentClientConventions : CatalogContentClientConventions
    {
        protected override void ApplyProductContentConventions(EPiServer.Find.ClientConventions.TypeConventionBuilder<ProductContent> conventionBuilder)
        {
            base.ApplyProductContentConventions(conventionBuilder);
            conventionBuilder
                .ExcludeField(x => x.Variations())
                .IncludeField(y => y.VariationContents());
        }
        public override void ApplyConventions(IClientConventions clientConventions)
        {
            base.ApplyConventions(clientConventions);
            // Do not index variationContent
            ContentIndexer.Instance.Conventions.ForInstancesOf<VariationContent>().ShouldIndex(x => false);
            SearchClient.Instance.Conventions.NestedConventions.ForInstancesOf<ProductContent>().Add(x => x.VariationContents());
        }
    }

We use the latest implementation of find: EpiServer.Find.Framework 13.0.5 and EpiServer.Find.Commerce 11.0.2 (And commerce 12.17.1)

Any idea?

Thanks in advance!