We recently upgraded to EPiServer 11, and when that happened the EPiServer.Url seems to stop working in a EditorDescriptor for page.

[EditorDescriptor(EditorDescriptorType = typeof(GameBrowserPuffEditorDesciptor))]
        public virtual IList CustomPuffs { get; set; }

public class GameBrowserPuffEditorDesciptor : CollectionEditorDescriptor where T : new()
    {
        public GameBrowserPuffEditorDesciptor() : base()
        {
            GridDefinition.DisableDndSorting = true;
            GridDefinition.ExcludedColumns.Add("Id");
        }
    }

public class GameBrowserPuff
    {
        public GameBrowserPuff()
        {
            if (Id == Guid.Empty) Id = Guid.NewGuid();
        }

        public Guid Id { get; }

        [Display(Order = 30, Name = "Url")]
        public virtual Url Url { get; set; }
    }

When publishing the page that contains the property the EPiServer.Url is emptied and results in a runtime error.

Is this not supported in EPiServer 11 anymore? Or is it replaced with something else?