Refit client returns cached responses despite no-cache headers and HttpMessageHandler

I'm experiencing a caching issue with Refit when calling Keycloak Admin API endpoints. Despite setting various no-cache headers and implementing a custom HttpMessageHandler, I'm still getting cached responses from previous requests.

Problem Description

When I create a new realm in Keycloak and immediately call the RealmsAll() method, it returns the old cached list (e.g., 5 realms instead of 6). However:

• Direct HttpClient calls work correctly (no caching)
• Postman requests work correctly
• Restarting the application and calling RealmsAll() returns the correct response

This suggests the issue is client-side caching within Refit, not server-side.

Same problem occurs on ClientsAll3() method also.

Current Setup

Refit Interface:

[Headers("Accept: application/json")]
[Get("/admin/realms")]
Task<IApiResponse<ICollection<RealmRepresentation>>> RealmsAll([Query] bool? briefRepresentation);

Service Registration

services.AddTransient<NoCacheHandler>();
var refitSettings = new RefitSettings
{
    ContentSerializer = new SystemTextJsonContentSerializer(new JsonSerializerOptions
    {
        PropertyNameCaseInsensitive = false,
        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
    })
};

services.AddRefitClient<IKeycloakAdminRESTAPI>(refitSettings)
    .AddHttpMessageHandler<KeycloakAdminAuthenticationHandler>()
    .AddHttpMessageHandler<NoCacheHandler>()
    .ConfigureHttpClient((serviceProvider, config) =>
    {
        var keycloakOptions = serviceProvider.GetRequiredService<IOptions<KeycloakOptions>>();
        config.BaseAddress = new Uri(keycloakOptions.Value.Url);
        
        config.DefaultRequestHeaders.CacheControl = new CacheControlHeaderValue
        {
            NoCache = true,
            NoStore = true,
            MustRevalidate = true,
            MaxAge = TimeSpan.Zero
        };
        config.DefaultRequestHeaders.Pragma.ParseAdd("no-cache");
    });

Custom NoCacheHandler:

public class NoCacheHandler : DelegatingHandler
{
    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {
        // Add no-cache headers
        request.Headers.Add("Cache-Control", "no-cache, no-store, must-revalidate");
        request.Headers.Add("Pragma", "no-cache");
        
        // Add unique timestamp to URL
        var uriBuilder = new UriBuilder(request.RequestUri);
        var query = System.Web.HttpUtility.ParseQueryString(uriBuilder.Query);
        query["_t"] = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds().ToString();
        uriBuilder.Query = query.ToString();
        request.RequestUri = uriBuilder.Uri;

        var response = await base.SendAsync(request, cancellationToken);
        
        // Clear response cache headers
        response.Headers.Remove("ETag");
        response.Headers.CacheControl = new System.Net.Http.Headers.CacheControlHeaderValue
        {
            NoCache = true,
            NoStore = true,
            MustRevalidate = true
        };

        return response;
    }
}

What I've Tried
Added Cache-Control: no-cache, no-store, must-revalidate headers Added Pragma: no-cache headers Added unique timestamp query parameter to each request Removed ETag headers from responses Configured HttpClient with no-cache settings Used custom HttpMessageHandler to modify requests/responses Set ConnectionClose = false and other HttpClient configurations

I've tried disabling caching on client side on Refit. Also tried HttpClient. Refit didn't worked as expected but HttpClient did.

Environment .NET 8 Refit 8.0.0 Keycloak Admin REST API Windows development environment