Singleton orchestrator doesn't work as described in the docs

[kiryvl2]

Hi,

this page
https://learn.microsoft.com/en-us/azure/azure-functions/durable/durable-functions-singletons?tabs=csharp

says that

There is a potential race condition in this sample. If two instances of HttpStartSingle execute concurrently, both function calls will report success, but only one orchestration instance will actually start. Depending on your requirements, this may have undesirable side effects.

My testing shows that in case of race condition (i.e. starter.StartNewAsync is called two times with the same instanceId) I'm getting InvalidOperationException with Message = "An Orchestration instance with the status Running already exists".
That means that only one function call will report success while the other one will throw exception and report HTTP 500 code.

Is there a mistake in the docs or did I misunderstand something? Thank you.