ServiceBusTrigger delayed for extended period of time before executing

#### Check for a solution in the Azure portal
Nothing found.

#### Investigative information

> This is a duplicated bug report of https://github.com/Azure/azure-functions-servicebus-extension/issues/116

The issue I am having is that my function with a `ServiceBusTrigger` goes dark for an extended period of time. In the linked bug report, there is a 12 hour gap of silence, then it caught up with all messages. Then, after a short period of normal behavior, it went silent again. I was able to force it to trigger by initiating a new deployment via Azure DevOps.

Please provide the following:
> The information provided here is not referring to a problem invocation. I'm hoping you can use this information to trace into the "dark" periods.

- Timestamp: 10/13/2020, 19:36:13
- Invocation ID: 2fb23b2e-8037-4e18-8538-be9c3efbc0b6
- Region: East US

The periods of silence were (all in Central time)

10/11 8:30am - 5:30pm
10/11 8:30pm - 5:30am (next day)
10/13 12:30pm - 2:15pm

#### Expected behavior

The `ServiceBusTrigger` should be firing automatically when new messages are available in the queue.

#### Actual behavior

The `ServiceBusTrigger` works for a period of time, then begins to stop triggering automatically. The first noticed period was 12 hours of silence, then it fired on it's own and caught up with all messages in the queue. Soon after, the message count rose and the functions didn't execute. There were no Application Insights logs to correlate this rising queue count. At the time of this writing, I just had this issue happen again, where the function didn't execute for around an hour. Triggering a new deployment via AzureDevOps caused the function to fire.

#### Known workarounds

Triggering a new deployment via AzureDevOps caused the function to fire.

#### Related information

Source

```csharp
[FunctionName("NotificationProcessor")]
public async Task Run([ServiceBusTrigger(ServiceBusNotificationsQueueName, Connection = ServiceBusConnectionName)] Message message,
MessageReceiver messageReceiver,
ILogger logger)
{
try
{
// read the message & process. based on the results, call abandon or complete.
// DoWork();
if (success)
{
await messageReceiver.AbandonAsync(message.SystemProperties.LockToken, modifiedProperties);
}
else
{
await messageReceiver.CompleteAsync(message.SystemProperties.LockToken);
}
}
catch (Exception ex)
{
await messageReceiver.AbandonAsync(message.SystemProperties.LockToken);
logger.LogError(ex, $"NotificationProcessor Error processing {message.MessageId}");
throw;
}
}
```

Start with the linked duplicate issue and the reported ServiceBusTrigger invocation details, including the listed silence periods and deployment workaround. Compare the expected automatic triggering with the observed queue buildup and missing Application Insights logs; done means identifying and documenting the cause of the extended trigger delays and confirming that messages execute without a deployment restart.

Written by the indexing model from the issue text.