Share cookies between ASP.NET 4.X and ASP.NET Core

I'm trying to use an authentication cookie that was generated in .NET 4.6.1 and use it in a .NET Core application. I found several articles that all give the same suggestion on how to do it:

https://docs.microsoft.com/en-us/aspnet/core/security/cookie-sharing?view=aspnetcore-2.1#sharing-authentication-cookies-between-aspnet-4x-and-aspnet-core-applications

The code looks like this:

app.UseCookieAuthentication(new CookieAuthenticationOptions
{
    AuthenticationType = "Identity.Application",
    CookieName = ".AspNet.SharedCookie",
    LoginPath = new PathString("/Account/Login"),
    Provider = new CookieAuthenticationProvider
    {
        OnValidateIdentity =
            SecurityStampValidator
                .OnValidateIdentity<ApplicationUserManager, ApplicationUser>(
                    validateInterval: TimeSpan.FromMinutes(30),
                    regenerateIdentity: (manager, user) =>
                        user.GenerateUserIdentityAsync(manager))
    },

    TicketDataFormat = new AspNetTicketDataFormat(
        new DataProtectorShim(
            DataProtectionProvider.Create(GetKeyRingDirInfo(), 
                (builder) => { builder.SetApplicationName("SharedCookieApp"); })
            .CreateProtector(
                "Microsoft.AspNetCore.Authentication.Cookies.CookieAuthenticationMiddleware",
                "Identity.Application",
                "v2"))),

    CookieManager = new ChunkingCookieManager()
});

The TicketDataFormat section in the options is what encrypts the cookie.

The problem is that the original cookie that's generated in 4.6.1 used to be about 4kb, but when I encrypt the cookie using the process described in the article the cookie balloons in size to about 58kb across 15 chunked cookies. This causes the site to send a 400 error because the response header is too large. I couldn't find a way to get these cookies any smaller.

Has anyone experienced this? How did you get around it?

Thank you.