AccessToken is null when using OpenIdConnect

I have a Blazor server-side app and in Startup.cs I have the following:

services.AddSingleton<ITicketStore, CookieMemoryTicketStore>();services.AddOptions<CookieAuthenticationOptions>(CookieAuthenticationDefaults.AuthenticationScheme)        .Configure<ITicketStore>((options, store) =>        {            options.ExpireTimeSpan = TimeSpan.FromDays(14);            options.SlidingExpiration = true;            options.SessionStore = store;        });

I use a ITicketStore implementation to store the cookies using MemoryCache. and then the authentication set up:

services.AddAuthentication(options =>{    options.DefaultAuthenticateScheme = CookieAuthenticationDefaults.AuthenticationScheme;    options.DefaultSignInScheme = CookieAuthenticationDefaults.AuthenticationScheme;    options.DefaultChallengeScheme = OpenIdConnectDefaults.AuthenticationScheme;}).AddCookie(CookieAuthenticationDefaults.AuthenticationScheme).AddOpenIdConnect(OpenIdConnectDefaults.AuthenticationScheme, options =>{    options.Authority = "authority";    options.ClientId = "clientid";    options.ClientSecret = "clientsecret";    options.ResponseType = OpenIdConnectResponseType.Code;    options.ResponseMode = OpenIdConnectResponseMode.FormPost;    options.GetClaimsFromUserInfoEndpoint = true;    options.MapInboundClaims = false;    options.SaveTokens = true;    options.UseTokenLifetime = false;    options.UseSecurityTokenValidator = true;    options.Scope.Add(OpenIdConnectScope.OpenIdProfile);    options.Scope.Add(OpenIdConnectScope.Email);    options.Scope.Add(OpenIdConnectScope.OfflineAccess);    options.TokenValidationParameters = new TokenValidationParameters    {        NameClaimType = "name",        RoleClaimType = "role"    };});services.AddAuthorizationCore();

And in my _Host.cshtml I do:

var tokens = new InitialApplicationState{    AccessToken = await HttpContext.GetTokenAsync(Token.Access),    IdToken = await HttpContext.GetTokenAsync(Token.Id),    RefreshToken = await HttpContext.GetTokenAsync(Token.Refresh),};

And the InitialApplicationState is then used in App.razor.

And during my login process (on login redirect from the auth provider), I start with:

var oidcOptions = new OidcClientOptions{    Authority = "issuer",    ClientId = "clientid",    LoadProfile = false,    Scope = StandardScopes.OpenId};var client = new OidcClient(oidcOptions);var state = await client.GetUserInfoAsync(tokenProvider.AccessToken, ct);

Using the above everything works fine for a few hours. Then all of a sudden, when the user is automatically authenticated (his authenication cookies are still stored in the browser), the call to GetUserInfoAsync fails with an exception because tokenProvider.AccessToken is null.

The only workaround so far is to delete all the site cookies and then authentication/authorization works again.

Has anyone encountered this problem? Is the above code missing some steps?