DRL Fault

I have an ongoing issue with one of my DRL strips. 

I bought the car approx 6 months ago, and the r/h DRL never worked. I recently got around to replacing the control module, and thankfully the DRL strip came back to life.

The current issue is, when the headlights come on at night, the "check r/h DRL" fault comes back on the dash. I have checked and it is working fine.

During the day, when only the DRL are on, without headlights, there is no faults. Something about the headlights coming on is triggering the fault.

Has anyone experienced something like this before?