Intensity Drop

check the touch pad if the bubble for intesity 1 is flat it is like someone pushing on it if you have a small suction cup you can try pulling it back and see if the intensity stays where you selected it. If you have two light swap the connection and see if the problem follows to the other light head

check for a stuck key, failing power supply. Has thee been any liquid, humidty issues before this happened? Any hardware changes?