OData 8.x with ASP.NET 5 always returns 401 Unauthorized on api endpoints

New ASP.NET 5 api project that is trying to use Bearer token authentication against OData 8 endpoints. All requests result in 401 Unathoized being returned as if the token is not even being checked.

The same code works fine with ASP.NET 5 and OData 7.x.

public void ConfigureServices(IServiceCollection services) {
	...
	if (Environment.IsLocal()) {
		services
			.AddAuthentication("BasicAuthentication")
			// MockAuthenticatedUser inherits from AuthenticationHandler for local development/testing purposes
			.AddScheme<AuthenticationSchemeOptions, MockAuthenticatedUser>("BasicAuthentication", null);
	}
	else {
		services.AddDistributedMemoryCache();

		services
			.AddAuthentication(IdentityServerAuthenticationDefaults.AuthenticationScheme)
			.AddIdentityServerAuthentication(options => {
				options.Authority = ssoSettings.BaseUri.ToString();
				options.ApiName = "xyz";
				options.ApiSecret = ssoSettings.ClientSecret;

				options.EnableCaching = true;
			});
	}
	...
	services.AddSwaggerGen(c => {
		...
	});
	...
	services
		.AddControllers(options => {
			var policy = new AuthorizationPolicyBuilder().RequireAuthenticatedUser().Build();
			options.Filters.Add(new AuthorizeFilter(policy));
		})
		.AddOData(opt => {
			opt
				.Count()
				...
				.AddRouteComponents("api", EdmModelBuilder.GetEdmModel());
		});
}

public void Configure(IApplicationBuilder app) {
	...
	app.UseAuthorization();
	app.UseAuthentication();

	app.UseEndpoints(endpoints => {
		endpoints
			.MapControllers()
			.RequireAuthorization();
	});
}

The issue does not seem to be specific to AddIdentityServerAuthentication(). During local development, using my MockAuthenticatedUser handler, the same 401 Unauthorized is returned. Breakpoints in the handler will trigger when Swagger page is viewed -- indicating that authentication is configured correctly -- but does not trigger when api requests are made.

Unable to find documentation or samples in this repo on proper configuration.