that is great to know and i will certainly check these points on the bike. Really useful as i had started looking at earth points near the lights themselves and all appeared fine.
there are a few points at which cable ties have been used.
these are the OEM lights and bars fitted by a Honda dealer (unfortuantely has now since sold the business)
Sounds like a loose ground. I dont know how the OEM lights are wired but I would start by checking the 12mm bolt under the left side panel. Bottom right in pic:

There is another ground point under the hinge of the tank, but I wouldn't think that would be tied to the lights.
If these lights have a separate ground point find that and check it.
Hopefully it's not a broken wire. Those usually occur when a cable tie is placed a point of repetitive stress causing the wire to fatigue, very hard to spot.