Hi, I have just replaced 5 x halogen mr16 bulbs with 5 x 4w led mr16. I changed the transformer to a 2a led driver. 4 of the bulbs work fine but one keeps slowly flashing on and off after about 15minutes of being switched on. Ive tried changing the bulb but had same problem with new bulb. Is there any obvious reason why it would do this? I checked the voltage and its at 11.97 volts. Is it just faulty bulbs or is it the driver causing this? And light on this would be appriciated.