That is the case with most preamps. Switch preamp on before power amps and power amps off before preamp.
It is actually very good as SS internal phonostages are concerned and will compare well to many outboard models . However it is very confusing to adjust for different cartridge output levels and loading requirements. Jumpers need to be fitted or moved around the circuit board using miniature fine nosed pliers or tweezers whilst paying close attention to the instruction manual. A total PITA.
Incidentally I much prefer using MC cartridges into step up transformers compared to high gain headamps and tubes over solid state.