Was the 430W in VLOC mode when this happened or was it trying to follow a GPS flight plan?
Are you sure you did not turn the knob when it was still in CRS mode?
Was the CDI needle green or magenta when you adjusted it? If it was Magenta you were only adjusting the GPS CRS in the 430W, it has to be green to adjust the CRS (OBS) on the 430W NAV radio side.