I had a phone call today from a man who said he had LED lights installed last November by a landscaper guy he knew and recently the the LEDs started flashing when they were on. I usually qualify callers, but in this case, by coincidence I had an appointment near him this afternoon so I arranged a time to take a look. Very nice home but I notice big box store integrated LED fixtures and a Hampton Bay transformer (Home Depot). I started at the beginning.... 118 volts coming out of the house. Turned on the transformer. Yep, LEDs are flashing (brightly). Touched my leads to the transformer lugs. Reading on my Fluke meter is 0.00. Went to one of the Quick Discs that were used for connections. Unscrewed the cap and touched the contacts. Reading is 0.00 while LEDs are still flashing. My conclusion is that the transformer is defective. But I don't understand how the LEDs worked in any way with a reading of 0.00 from the transformer. Obviously, I am not going to work on this amateur system but I am still curious about what I found. What's the answer?