Can anyone decipher this error? I could not find another post on it or any other resources to explain in more detail.

It happens when trying to preview a form or display the form anywhere in the process to a user.

This error is thrown and it does not allow access to the form. The workaround has been to copy the entire process and re-publish as a new process, but then you lose your history.

Inner exception: System.InvalidCastException
Message: Unable to cast object of type 'System.Data.Entity.DynamicProxies.cf_forms_3C41E27BE29C1414189B8A395E00BA02D82890E1368643617A4AC44EC5ED2348' to type 'Laserfiche.Forms.EntityModels.cf_theme'.
   at Laserfiche.Forms.EntityModels.Services.FunctionCacheService.<>c__DisplayClass4_0`2.<Memoize>b__0(TArg param)
   at E_Forms.Models.ViewModels.Form._BaseFormModel._PopulateFormValues(Int32 formId)
   at E_Forms.Models.ViewModels.Form._BaseFormModel.PopulateFormValues(Int32 formId)
   at E_Forms.Controllers.FormController.NewSubmission(Int32 formId, String mode, Int32 instanceId, Int32 loadDb, Boolean HideHeader)
   at lambda_method(Closure , ControllerBase , Object[] )
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c.<BeginInvokeSynchronousActionMethod>b__9_0(IAsyncResult asyncResult, ActionInvocation innerInvokeState)
   at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult)
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult)
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass11_0.<InvokeActionMethodFilterAsynchronouslyRecursive>b__0()
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass11_2.<InvokeActionMethodFilterAsynchronouslyRecursive>b__2()
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass11_2.<InvokeActionMethodFilterAsynchronouslyRecursive>b__2()
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult)
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass3_6.<BeginInvokeAction>b__4()
   at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass3_1.<BeginInvokeAction>b__1(IAsyncResult asyncResult)