I recently had an electrician install 7 recessed can lights on the same 3 way circuit. The circuit has a 3 way dimmer on it and the fixtures all have dimable 15 watt LED bulbs.

The problem is that sporadically, the lights will flicker.. . All of the lights together. It doesn't seem to be tied to any of the obvious things like the A/c kicking on or off.. . Use of cell or cordless phones. The flicker does go away when the lights are dimmed to about 25%. There are times when the lights do not flicker although it is becoming less and less. Yesterday, I had the electrician change out the 3 way dimmer and nothing changed.