ApplyQueryHints throws Collection was modified; enumeration operation may not execute

I use _context.NextQueryHints.Add(SqlServerTools.Sql.OptionRecompile); in several part of my code. and I register the connection as scoped in DI. sometimes when my services are under load, I get this exception

Exception message:
Collection was modified; enumeration operation may not execute.
Stack trace:
   `"trace":"   at System.Collections.Generic.List`1.Enumerator.MoveNextRare()\r\n   at LinqToDB.SqlProvider.BasicSqlBuilder.ApplyQueryHints(String sql, List`1 queryHints)\r\n   at LinqToDB.Data.DataConnection.InitCommand(CommandType commandType, String sql, DataParameter[] parameters, List`1 queryHints, Boolean withParameters)\r\n   at LinqToDB.Data.DataConnection.QueryRunner.ExecuteReaderAsync(CancellationToken cancellationToken)\r\n   at LinqToDB.Linq.QueryRunner.ExecuteQueryAsync[T](Query query, IDataContext dataContext, Mapper`1 mapper, Expression expression, Object[] ps, Object[] preambles, Int32 queryNumber, Func`2 func, TakeSkipDelegate skipAction, TakeSkipDelegate takeAction, CancellationToken cancellationToken)\r\n   at LinqToDB.Linq.ExpressionQuery`1.GetForEachAsync(Action`1 action, CancellationToken cancellationToken)\r\n   at LinqToDB.AsyncExtensions.ToListAsync[TSource](IQueryable`1 source, CancellationToken token)\r\n   at WebApi.Commands.MarketInfo.StockVolumeChartReadingCommand.StockVolumeChartReadingHandler.Handle(StockVolumeChartReadingCommand request, CancellationToken cancellationToken) in D:\\Workspaces\\New Mdp\\WebApi\\Commands\\MarketInfo\\StockVolumeChartReadingCommand.cs:line 69\r\n   at MediatR.Pipeline.RequestExceptionProcessorBehavior`2.Handle(TRequest request, CancellationToken cancellationToken, RequestHandlerDelegate`1 next)\r\n   at MediatR.Pipeline.RequestExceptionProcessorBehavior`2.Handle(TRequest request, CancellationToken cancellationToken, RequestHandlerDelegate`1 next)\r\n   at MediatR.Pipeline.RequestExceptionActionProcessorBehavior`2.Handle(TRequest request, CancellationToken cancellationToken, RequestHandlerDelegate`1 next)\r\n   at MediatR.Pipeline.RequestExceptionActionProcessorBehavior`2.Handle(TRequest request, CancellationToken cancellationToken, RequestHandlerDelegate`1 next)\r\n   at MediatR.Pipeline.RequestPostProcessorBehavior`2.Handle(TRequest request, CancellationToken cancellationToken, RequestHandlerDelegate`1 next)\r\n   at MediatR.Pipeline.RequestPreProcessorBehavior`2.Handle(TRequest request, CancellationToken cancellationToken, RequestHandlerDelegate`1 next)\r\n   at WebApi.Controllers.MarketInfoController.StockVolumeChartReadingCommand(StockVolumeReadingChartRequest request) in D:\\Workspaces\\New Mdp\\WebApi\\Controllers\\MarketInfoController.cs:line 31\r\n   at lambda_method1763(Closure , Object )\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.AwaitableObjectResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Awaited|12_0(ControllerActionInvoker invoker, ValueTask`1 actionResultValueTask)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()\r\n--- End of stack trace from previous location ---\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)\r\n   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)\r\n   at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)\r\n   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)\r\n   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)\r\n   at WebApi.Middlewares.ApiExceptionHandlingMiddleware.Invoke(HttpContext context) in D:\\Workspaces\\New Mdp\\WebApi\\Middlewares\\ApiExceptionHandlingMiddleware.cs:line 37",`

there is one part of my code that I use OptionRecompile :

 var query = _context.FinalScreeners.With("NoLock").AsQueryable();
                query = query.Where(x => x.TradeDate >= request.Request.FromDate);
                query = query.Where(x => x.TradeDate.Date <= request.Request.ToDate);
                _context.NextQueryHints.Add(SqlServerTools.Sql.OptionRecompile);

                return await query.Select(x => new StockVolumeReadingChartResponse
                {
                    TradeDate = x.TradeDate,
                    Isin = x.Isin,
                }).SetOrdering(request.Request.Sort).ToListAsync(token: cancellationToken);

Environment details

linq2db version: 3.2.3 Database Server: Sql Server 2019 Database Provider: ? Operating system: Windows Server 2019 .NET Framework: Net 5.0.2

[sdanyliv]

Never change MappingSchema.Default in that way, Create new MappingSchema and add to DataConnection

var ms = new MappingSchema();
var mapper = ms.GetFluentMappingBuilder();
RealLegalTradeHistoricalFluentMap.Map(mapper);
...
services.AddLinqToDbContext<AppDataConnection>((provider, options) =>
           {
               options
               .UseSqlServer(currentConnectionString)
               .UseMappingSchema(ms);

               if (_logDbCommands)
                   options.UseDefaultLogging(provider);
           });

[MostafaEsmaeili]

Update: I have another exception: Collection was modified; enumeration operation may not execute this time it accrues on fluent map class :

this is fluentMap class :

public static class RealLegalTradeHistoricalFluentMap
    {
        public static void Map(FluentMappingBuilder mapper)
        {
            mapper.Entity<RealLegalTradeHistoricalEntity>().HasTableName("RealLegalTradeHistorical")
                .HasSchemaName("dbo")
                .Property(x => x.Id).IsPrimaryKey().IsIdentity().HasSkipOnInsert().HasSkipOnUpdate()
           .Property(x => x.Isin)
                .HasLength(12)
                .HasDataType(LinqToDB.DataType.VarChar)
                .IsNullable(false)

            .Property(x => x.InsCode)
                 .HasDataType(LinqToDB.DataType.VarChar)
                 .HasLength(50)
                 .IsNullable(false)

            .Property(x => x.RealSellVolume)
                .IsNullable()
                .HasPrecision(18).HasScale(0)

            .Property(x => x.RealSellACount)
                .IsNullable()
                .HasPrecision(18).HasScale(0)

            .Property(x => x.RealBuyVolume)
                .IsNullable()
                .HasPrecision(18).HasScale(0)

            .Property(x => x.RealBuyCount)
                .IsNullable()
                .HasPrecision(18).HasScale(0)

            .Property(x => x.LegalSellVolume)
                .IsNullable()
                .HasPrecision(18).HasScale(0)

            .Property(x => x.LegalSellACount)
                .IsNullable()
                .HasPrecision(18).HasScale(0)

            .Property(x => x.LegalBuyVolume)
                .IsNullable()
                .HasPrecision(18).HasScale(0)

            .Property(x => x.LegalBuyCount)
                .IsNullable()
                .HasPrecision(18).HasScale(0)

            .Property(x => x.Date)
                .IsNullable(false)

            .Property(x => x.Created)
                .IsNullable();
        }

    }

I Add this class to my context this way :

 public AppDataConnection(LinqToDbConnectionOptions<AppDataConnection> options)
            : base(options)
        {
            var mapper = MappingSchema.Default.GetFluentMappingBuilder();
            ...
            RealLegalTradeHistoricalFluentMap.Map(mapper);
            ...
          
        }

and new StackTrace :

 ---> System.InvalidOperationException: Collection was modified; enumeration operation may not execute.
   at System.Collections.Generic.List`1.Enumerator.MoveNextRare()
   at System.Linq.Enumerable.OfTypeIterator[TResult](IEnumerable source)+MoveNext()
   at System.Collections.Generic.LargeArrayBuilder`1.AddRange(IEnumerable`1 items)
   at System.Collections.Generic.EnumerableHelpers.ToArray[T](IEnumerable`1 source)
   at LinqToDB.Metadata.FluentMetadataReader.GetAttributes[T](Type type, MemberInfo memberInfo, Boolean inherit)
   at System.Linq.Enumerable.SelectManySingleSelectorIterator`2.ToArray()
   at System.Linq.Enumerable.SelectManyIterator[TSource,TCollection,TResult](IEnumerable`1 source, Func`2 collectionSelector, Func`3 resultSelector)+MoveNext()
   at System.Collections.Generic.LargeArrayBuilder`1.AddRange(IEnumerable`1 items)
   at System.Collections.Generic.EnumerableHelpers.ToArray[T](IEnumerable`1 source)
   at LinqToDB.Mapping.MappingSchema.GetAttributes[T](Type type, MemberInfo memberInfo, Func`2 configGetter, Boolean inherit, Boolean exactForConfiguration)
   at LinqToDB.Mapping.EntityMappingBuilder`1.<SetAttribute>g__SetAttr|48_0[TProperty,TA](Expression e, Boolean m, <>c__DisplayClass48_0`2& )
   at LinqToDB.Mapping.EntityMappingBuilder`1.SetAttribute[TProperty,TA](Expression`1 func, Boolean processNewExpression, Func`2 getNew, Action`2 modifyExisting, Func`2 configGetter, Func`2 overrideAttribute, Func`2 existingGetter)
   at LinqToDB.Mapping.PropertyMappingBuilder`2.SetColumn(Action`1 setColumn)
   at CommonObjects.Linq2DbSettings.Mapping.RealLegalTradeHistoricalFluentMap.Map(FluentMappingBuilder mapper) in D:\Project\CommonObjects\Linq2DbSettings\Mapping\RealLegalTradeHistoricalFluentMap.cs:line 67
   at CommonObjects.Linq2DbSettings.AppDataConnection..ctor(LinqToDbConnectionOptions`1 options) in D:\Project\CommonObjects\Linq2DbSettings\AppDataConnection.cs:line 80

I emphasize again that this service works properly in most cases with this configuration. and now when I change my fluent map classes and remove all property configuration, The services work properly under load (till now)

 public static void Map(FluentMappingBuilder mapper)
        {
            mapper.Entity<RealLegalTradeHistoricalEntity>().HasTableName("RealLegalTradeHistorical")
                .HasSchemaName("dbo")
                .Property(x => x.Id).IsPrimaryKey().IsIdentity().HasSkipOnInsert().HasSkipOnUpdate();
         
        }