At startup the knobs to change frequency are connected to th eCOM part of the GNS530, as can be seen on the display. To change to NAV press and hold LH mouse button on the inner com/vloc rotary knob (it turns yellow), then click RH mouse button. Then change the STBY NAV frequency (to 111.30 for KNEW 18R) and press V with up/down arrows to activate it.
Nothing wrong with KNEW 38R ILS. I flew the leg on AP corrrectly (also flew it on AP in the G3000 version without any issues).