Not a common problem. sounds like a short between wires. Before you tear the bike apart, try to narrow down where it might be happening. Move the handlebars fully in both directions and see if there is any change in the lights' behavior, which could narrow down where the short is. Put the bike's ignition in 'park'. That should cut power to the running lights in the front signals, but the hazards/blinkers should work. Could give a clue as to which wire the stray voltage is coming from.