My neutral LED has slowly been getting dimmer and now it's out, but sometimes it jumps back up and it's bright green. Sound like an electrcal issue or an LED failure? I think my oil LED is beginning to do the same thing.
Did you replace them with LEDs? Stock ones are just little light bulbs.
Either way, you probally have a corroded connection somewhere. start pulling apart your connections, starting with where your bulb plugs in, and clean everything up with contct cleaner and a wire brush if possable. Then put some dielectric grease in there and put it back together. this will keep out the water and corosion.
Been riding/parking in the rain much lately? If you live near the sea, the problem is worse.