GAIA-2's OSC2/3 emulates analog oscillators.
By setting the Click Type to "NATURAL" on each oscillators, you will the different attack feel (different waveform phase) every time you strike the key.
Press the [ENTER] knob to show the SOUND screen on the display, and set the Click Type to "NATURAL" in the EDIT screen of OSC2 and/or OSC3.