[BUG] [Service Bus] Can't create session when the connection is closing

[Mortana89]

Describe the bug
We get like constant errors (100dreds per hour) in our debugger console and AI about service bus.
One of them is an InvalidOperationException:
Can't create session when the connection is closing.

This is happening when using the built-in message pump mechanism. This message pump uses the following code:

 async Task SessionPumpTaskAsync()
        {
            while (!this.pumpCancellationToken.IsCancellationRequested)
            {
                var concurrentSessionSemaphoreAcquired = false;
                try
                {
                    await this.maxConcurrentSessionsSemaphoreSlim.WaitAsync(this.pumpCancellationToken).ConfigureAwait(false);
                    concurrentSessionSemaphoreAcquired = true;

                    await this.maxPendingAcceptSessionsSemaphoreSlim.WaitAsync(this.pumpCancellationToken).ConfigureAwait(false);

// THIS LINE THROWS THE ERROR
                    var session = await this.client.AcceptMessageSessionAsync().ConfigureAwait(false);
                    if (session == null)
                    {
                        await Task.Delay(Constants.NoMessageBackoffTimeSpan, this.pumpCancellationToken).ConfigureAwait(false);
                        continue;
                    }

When breaking on that exception, I can see the client's 'IsClosedOrClosing' property is false, while the exception says otherwise:

However, when going deeper, in the SessionClient.AcceptMessageSessionAsync, I can see that the session is closed/closing;

Using .NET Core 3.1, and Microsoft.Azure.ServiceBus 4.1.2 version.

[ghost]

Thanks for the feedback! We are routing this to the appropriate team for follow-up. cc @jfggdl.

[nemakam]

Duplicate of #9416.

[nemakam]

@Mortana89
Are you closing the queueClient/subClient when you get this exception?

[nemakam]

I'm going to close this issue. Please respond back in the original thread to have a single place for tracking purposes