summary() of fitted mxModel object returns error

> ACENonScSLCoraFit
MxModel 'ACENonScSLCora'
type : default
$matrices :
$algebras : 'modelfit'
$constraints :
$intervals :
$latentVars : none
$manifestVars : none
$data : NULL
$submodels : 'ACE'
$expectation : NULL
$fitfunction : MxFitFunctionAlgebra
$compute : NULL
$independent : FALSE
$options :
$output : TRUE
> summary(ACENonScSLCoraFit)
Error in observedStatisticsHelper(model, expectations[[i]], datalist, :
trying to get slot "type" from an object of a basic class ("NULL") with no slots


compute plan:
MxComputeSequence 'compute'
$freeSet : '.'
steps[[ 1 ]] :
MxComputeGradientDescent 'compute'
$freeSet : '.'
$engine : 'CSOLNP'
$fitfunction : '21'
$verbose : 0
steps[[ 2 ]] :
MxComputeNumericDeriv 'compute'
$freeSet : '.'
$fitfunction : 21
$parallel : TRUE
$stepSize : 1e-04
$iterations : 4
$verbose : 0
steps[[ 3 ]] :
MxComputeStandardError 'compute'
$freeSet : '.'
steps[[ 4 ]] :
MxComputeReportDeriv 'compute'
$freeSet : '.'


If we are going to be as verbose as this, perhaps the $fitfunction should be in terms of the actual function, not the code for it? Also, the number of function evaluations in each step would, IMO, be more useful to return than the number of iterations.