microsoft-identity-web: [Bug] "The issuer '(null)' is invalid" error when I request my API with bearer token

Which Version of MSAL are you using ? msal.net 1.9.0

Platform asp.net core 5.0

What authentication flow has the issue?

• Desktop / Mobile
  • Interactive
  • Integrated Windows Auth
  • Username Password
  • Device code flow (browserless)
• Web App
  • Authorization code
  • OBO
• Daemon App
  • Service to Service calls

Other? - please describe;

Is this a new or existing app? This is a new app or experiment

Repro

I have added following lines of code.

// startup.cs
services.AddMicrosoftIdentityWebApiAuthentication(Configuration, "AzureAd");
app.UseAuthentication();

// WeatherForecastController
[Authorize]
[RequiredScope("Default")]

// appsettings.json
"AzureAd": {
    "Instance": "https://login.chinacloudapi.cn/",
    "ClientId": "my client id",
    "Domain": "my organization domain",
    "TenantId": "my organization tenant id",
    "Authority": "https://login.chinacloudapi.cn/my organization tenant id/"
}

Expected behavior I checked my token on jwt.ms, it shows everything is good.

Actual behavior I use Postman to request the API, and the API tells me issuer is null in my token.