I have an issue that is happening in my Azure Function and Service Bus usage with Mass Transit implementation. I have attached the repository where the issue is shown. Before running it, you need to fill the connection string in ProblemWithMassTransit/Program.cs - variable con. And you also need to fill this connection string in ProblemWithMassTransitFunctions/localsettings.json.

The point is that when the TestMessage is published, it is captured by Function1, which passes it to the Mass Transit consumer. It encounters a problem and throws an exception. The correct way is to publish the Fault message which is done by Mass Transit. However, Function1 is called again in the next step and it is called again until max delivery attempt - 10. Yet, autocomplete is set to true in host.json and Mass Transit documentation says that in that case Mass Transit will try to mark the message as processed.

How to solve this? Is this a Mass Transit issue or an Azure function issue? Unfortunately I can't find a solution on the internet.

Test repository -

Thank you very much