Open Channel settings-> insert LC and/or HC settings as you wish-> Save track preset->load any other track preset and then load the last one saved with LC/HC settings. The LC/HC settings were not saved.
I thought this too, but on my system it turns out they are there - just not actually activated so loaded but in the “off” state - double click the power button by the filters rack & they should come back to life.
The same thing also happens when you save just a filter rack in a track preset too - it saves it, it loads it back but powered off.