Method client.GetReadResultAsync is getting cycling

> Please provide us with the following information:
> ---------------------------------------------------------------

### This issue is for a: (mark with an `x`)
```
- [ x] bug report -> please search issues before submitting
- [ ] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
>
ReadOperationResult results;

do
{
**results = await client.GetReadResultAsync(Guid.Parse(operationId));**
}
while ((results.Status == OperationStatusCodes.Running || results.Status == OperationStatusCodes.NotStarted));

var textUrlFileResults = results.AnalyzeResult.ReadResults;
foreach (ReadResult page in textUrlFileResults)
{
foreach (Line line in page.Lines)
{
stb.AppendLine(line.Text);
}
}

### Any log messages given by the failure
> The code is an ASP.NET Core 3.1API was working fine from a month but since today stop working, I debug the code and saw that the do while is cycling and the results.Status property is always with Running value

### Expected/desired behavior
>

### OS and Version?
> Windows 7, Windows Server 2012

### Versions
> asp.net core 3.1

### Mention any other details that might be useful
was working fine but just stop working
> ---------------------------------------------------------------
> Thanks! We'll be in touch soon.

Start with the reported do/while loop around client.GetReadResultAsync(Guid.Parse(operationId)) and reproduce the behavior using the stated ASP.NET Core 3.1 setup. Check the returned OperationStatusCodes and operationId over repeated calls; done means identifying why the status remains Running and documenting or correcting the behavior, since no project file or test is named.

索引モデルが issue の本文から書いたものです。