Since the release of Pro Tools 12.7 Pro Tools HD/HDX/HD Native hardware defaults to 192 kHz sample rate when Pro Tools is closed on Mac systems, which causes connected RedNet 5/HD32Rs to switch into Expansion Mode. Expansion Mode causes the RedNet unit to be seen as a 16 I/O device. 

This behaviour is due to the fact that the RedNet follows the sample rate of the Pro Tools HD/HDX hardware. Fortunately this can be resolved by manually adjusting the sample rate of the HD/HDX card from within Audio MIDI Setup (Applications > Utilities > Audio MIDI Setup) when Pro Tools is closed.

Change the sample rate for the HD/HDX/HD Native card to the desired value then open RedNet Control and click on the wrench/gear icon located next to the RedNet unit in question and uncheck the Expansion Mode box.

The RedNet 5/HD32R should now retain the sample rate set in Audio MIDI Setup whenever Pro Tools is closed.