P value of 1 in mxCompare

Hello,
I am working on an analysis of a univariate sex limitation model for depression and I have run into a potential problem. When comparing the homogeneity ACE model to the AE model, I get a p-value of 1 in mxCompare. The fit of the models are very similar:

> mxCompare(HomACEModelFit,HomAEModelFit)
    base           comparison   ep   minus2LL      df          AIC        diffLL                 diffdf      p
1 HomACE       <NA>            4     16217.9      21258   -26298.1   NA                     NA       NA
2 HomACE      HomAE           3    16217.9       21259   -26300.1 -1.426603e-05    1         1

Does this mean there is something wrong with the models, or is open mx rounding off the value? When I compare them to the full heterogeneity model it works fine and I get p values of 0.20 and 0.12.
Due to confidentiality reasons I am not able to include the data but I have attached the script for the models.
Any input would be greatly appreciated,
Kind regards/
Lisa