curious sql exception occured when calling UnitOfWork#SaveChanges()

We use LightSpeed v3.1.(Mindscape.LightSpeed.dll version is 3.1.2673.17134) on production environment.

I encountered a curious SQL Exception recently on production,

but I couldn't reproduce this exception on local environment..

Below code(Uow.SaveChanges) raised the exception.

----------------------------------------------------

var signupSessionData = Uow.FindById<SignupSessionData>(id);

if (signupSessionData.data != data)

{

    signupSessionData.data = data;

    Uow.SaveChanges();                // raise SQL Exception!! 

}

----------------------------------------------------

[Exception detail] 

System.Data.SqlClient.SqlException (0x80131904): Must declare the scalar variable "@p1".
Must declare the scalar variable "@p1".
  at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
  at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning()
  at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
  at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
  at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async)
  at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result)
  at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)
  at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
  at  . . .€()
  at  . .€(IUnitOfWork , IDbCommand ,   )
  at  . .€(  )
  at  . .€(IEnumerable`1 )
  at  . . ()
  at  . .€(UnitOfWorkBase , IEnumerable`1 , IEnumerable`1 )
  at Mindscape.LightSpeed.UnitOfWork.SaveChanges(Boolean reset)
  at ......

---------------------------------------------------- 

Could you have any ideas why this exception occured ?

Thanks, nabehiro

There's no obvious reason from your example why this should happen.  We might be able to make a guess if we saw the model, but even then I'm not optimistic unless you can identify what's different between the production and local scenarios (and thereby obtain a repro case).

If you can repeat the error in production (but not locally) then one thing you could do is hook up a logger (LightSpeedContext.Logger, LightSpeedContext.VerboseLogging) and capture the generated SQL.  That might give us some sort of clue as to what the mystery @p1 is doing...