That could be where you are holding the wheel. It seems you need to hold away from the spokes. If you just hook your hand around a spoke, it does not sense you are holding the wheel.On my Niro the "hands on wheel" symbol only appears if I haven't moved the wheel for 15 seconds. It will do it irrespective of how many hands I use to hold the wheel.
Mine used to beep all the time when I 1st got it. Think most were due to LKA. Now after 6 months I seem to have been trained to drive within the lines as I very rarely get any beeps now.