Masstransit with RabbitMQ, message delivered twice after a correct handling of the consumer - rabbitmq

Question

I'have this configuration of MassTransit (RabbitMQ) on my consumer. The retry policy is to resend messages when there is any Timeout for a max of 5 intervals.
ep.ConfigureConsumer<T>(ctx,
c => {
c.UseMessageRetry(r =>
{
r.Interval(5, TimeSpan.FromMinutes(30));
r.Handle<Exception>(m => m.GetFullMessage().Contains("Timeout"));
r.Ignore(typeof(ApplicationException));
});
c.UseConcurrentMessageLimit(1);
});
ep.Bind(massTransitSettings.ExchangeName, y =>
{
y.Durable = true;
y.AutoDelete = false;
y.ExchangeType = massTransitSettings.ExchangeType;
y.RoutingKey = massTransitSettings.RoutingKey;
});
});
Everything works fine except when, sometimes, two consecutive timeouts occur of the same message;
Here a part of log file for message id: fa300000-56b5-0050-e012-08d9f39bc934
19/02/2022 12:34:28.699 - PAYMENT INCOMING Message -> Sql timeout, retry in 30 min
19/02/2022 13:04:28.572 - PAYMENT INCOMING Message -> 2th Sql timeout, retry in 30 min
19/02/2022 13:34:59.722 - PAYMENT INCOMING Message -> Process ok
19/02/2022 13:35:13.983 - PAYMENT HANDLED Message -> Message handled (74 secs)
19/02/2022 13:35:31.606 - PAYMENT INCOMING Message -> This should not incoming, causing an Application Exception (message in _error queue)
Where am I wrong?

Answer 1

You can't use message retry for intervals that long, since RabbitMQ has a default consumer timeout of 30 minutes. Per the documentation:
MassTransit retry filters execute in memory and maintain a lock on the message. As such, they should only be used to handle short, transient error conditions. Setting a retry interval of an hour would fall into the category of bad things. To retry messages after longer waits, look at the next section on redelivering messages.
For longer retry intervals, use message redelivery (sometimes called second-level retry). If you're using RabbitMQ, the built-in delayed redelivery requires the delayed-exchange plug-in. Or you can use an external message scheduler.