Launch Fluent in standalone. Set up the model. Save case & data in CFF (HDF format). Run model & save in CFF. It's entirely down to the legacy format not retaining adaption register data: the format predates adaption. CFF (HDF) has been developed to retain more information as well as work more efficiently in parallel. The only drawback of CFF is it can be marginally less reliable: most likely due to the parallel data passing.