I play the same bass, a G&L JB. I can find the same thing some times with the input knob. Although I’d consider the pickups hit for passive, they are still passive when it comes to filter pedals. It works a bit better if you have a little boost before the spectrum or if I put the knob at about 2:30 to 3:00 (or higher to taste) on the knob.
The alternate middle toggle position and to me sometimes other presets can sound like you are explaining until I adjust the sensitivity, which you get to by pressing the back button and then the input knob while the small middle light blinks. I can now hear now when it needs more sensitivity, the blend really helps with clarity as well I find.
After you get the sound you’re looking for with all settings, depress the foot switch and hold it down until the light blinks 3 times, then it’s saved. It’s a great pedal, the app really helps to understand how the pedal works and it’s tweakability. I like the computer app a little better than the phone app, until I understood how it was working, now can I can use the phone app as well.
Take some time with it and then you’ll love it.