Could you confirm "4 DECK Mixer Panel" on GUI?
1.press the [MIXER] button in the upper-left corner
2.change layout mode to [4 Deck horizontal] or [4 Deck vertical]
Are all knobs(Trim / EQ) on GUI set to same position?
Are all channel faders on GUI set to same position?
Knob will be set to 0 o'clock if you double-click on the knob.