Big chance that either the dark green or dark brown of the indicator live feed, has been mistaken for a black earth, they are hard to tell them apart, especially in bad light.
Gonna have to look its happening again! Bloody hate electrics so much!! Will get it sorted!!
Take headlight cowl off, then take the headlight off and see if you can see any wires loose there.
If not there, probably a loose wire elsewhere, hopefully its a easy fix, because if you have to pull all the insulating off the loom to find it, its a right ball ache.