✅ .NET 8 enum to string serialization throws an exception

public sealed record GetLinkMetricsRequest
{
    [FromRoute]
    public string Id { get; set; }
    
    [FromQuery]
    public TimePeriodUnit? TimeUnit { get; set; } = TimePeriodUnit.Day;
    
    [FromQuery]
    public int? Units { get; set; }
}

[JsonSourceGenerationOptions(UseStringEnumConverter = true)]
[JsonSerializable(typeof(GetLinkMetricsRequest))]
public partial class TimePeriodUnitJsonContext : JsonSerializerContext;


// applied to the Controllers
var options = new JsonSerializerOptions
{
    TypeInfoResolver = JsonTypeInfoResolver.Combine(ContextA.Default, ContextB.Default, ContextC.Default);
};

An unexpected error occurred. See the inner exception for details. System.NotSupportedException: JsonTypeInfo metadata for type 'AnalyticsService.Api..' was not provided by TypeInfoResolver of type 'System.Text.Json.Serialization.Metadata.JsonTypeInfoResolverWithAddedModifiers'. If using source generation, ensure that all root types passed to the serializer have been annotated with 'JsonSerializableAttribute', along with any types that might be serialized polymorphically.