var updateStatement = new UpdateOneModel<MyEntity>(
    matchFilter1 & matchFilter2,
    Builders<MyEntity>.Update
        .Set(x => x.MyArray[-1].ArrayItem, newValue); 

MongoDB.Driver.Linq.ExpressionNotSupportedException: Expression not supported: x.MyArray.get_Item(-1) because negative indexes are not valid. To use the positional operator $ use FirstMatchingElement instead of an index value of -1.
   at MongoDB.Driver.Linq.Linq3Implementation.Translators.ExpressionToFilterTranslators.ToFilterFieldTranslators.ArrayIndexExpressionToFilterFieldTranslator.Translate(TranslationContext context, Expression expression, Expression fieldExpression, Expression indexExpression)
   at MongoDB.Driver.Linq.Linq3Implementation.Translators.ExpressionToFilterTranslators.ToFilterFieldTranslators.GetItemMethodToFilterFieldTranslator.Translate(TranslationContext context, MethodCallExpression expression)
   at MongoDB.Driver.Linq.Linq3Implementation.Translators.ExpressionToFilterTranslators.ToFilterFieldTranslators.MethodCallExpressionToFilterFieldTranslator.Translate(TranslationContext context, MethodCallExpression expression)
   at MongoDB.Driver.Linq.Linq3Implementation.Translators.ExpressionToFilterTranslators.ToFilterFieldTranslators.ExpressionToFilterFieldTranslator.Translate(TranslationContext context, Expression expression)
   at MongoDB.Driver.Linq.Linq3Implementation.Translators.ExpressionToFilterTranslators.ToFilterFieldTranslators.MemberExpressionToFilterFieldTranslator.Translate(TranslationContext context, MemberExpression memberExpression)
   at MongoDB.Driver.Linq.Linq3Implementation.Translators.ExpressionToFilterTranslators.ToFilterFieldTranslators.ExpressionToFilterFieldTranslator.Translate(TranslationContext context, Expression expression)
   at MongoDB.Driver.Linq.Linq3Implementation.LinqProviderAdapterV3.TranslateExpressionToField[TDocument,TField](Expression`1 expression, IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry, Boolean allowScalarValueForArrayField)
   at MongoDB.Driver.ExpressionFieldDefinition`2.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry, LinqProvider linqProvider, Boolean allowScalarValueForArrayField)
   at MongoDB.Driver.ExpressionFieldDefinition`2.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry, LinqProvider linqProvider)
   at MongoDB.Driver.OperatorUpdateDefinition`2.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry, LinqProvider linqProvider)
   at MongoDB.Driver.CombinedUpdateDefinition`1.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry, LinqProvider linqProvider)
   at MongoDB.Driver.CombinedUpdateDefinition`1.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry, LinqProvider linqProvider)
   at MongoDB.Driver.CombinedUpdateDefinition`1.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry, LinqProvider linqProvider)
   at MongoDB.Driver.CombinedUpdateDefinition`1.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry, LinqProvider linqProvider)
   at MongoDB.Driver.CombinedUpdateDefinition`1.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry, LinqProvider linqProvider)
   at MongoDB.Driver.CombinedUpdateDefinition`1.Render(IBsonSerializer`1 documentSerializer, IBsonSerializerRegistry serializerRegistry, LinqProvider linqProvider)
   at MongoDB.Driver.MongoCollectionImpl`1.ConvertWriteModelToWriteRequest(WriteModel`1 model, Int32 index)
   at System.Linq.Enumerable.SelectIterator[TSource,TResult](IEnumerable`1 source, Func`3 selector)+MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at MongoDB.Driver.Core.Operations.BulkMixedWriteOperation..ctor(CollectionNamespace collectionNamespace, IEnumerable`1 requests, MessageEncoderSettings messageEncoderSettings)
   at MongoDB.Driver.MongoCollectionImpl`1.CreateBulkWriteOperation(IClientSessionHandle session, IEnumerable`1 requests, BulkWriteOptions options)
   at MongoDB.Driver.MongoCollectionImpl`1.BulkWriteAsync(IClientSessionHandle session, IEnumerable`1 requests, BulkWriteOptions options, CancellationToken cancellationToken)
   at MongoDB.Driver.MongoCollectionImpl`1.UsingImplicitSessionAsync[TResult](Func`2 funcAsync, CancellationToken cancellationToken)