Sometimes an LED bulb can flash when the power is turned off. Usually a tiny flash is seen every few minutes. The cause of this is induced voltage in the cable feeding the light. In a 2 way circuit, an extra wire containing 3 conductors runs between the 2 switches. Because they are parralel over a long distance, voltage is induced. Although very small, it is enough to give the LED a tiny flicker every so often. 

Solution: this excess voltage must be drained away. There are several methods:

1. Swap conductors. Often the centre conductor is used as the light feed. This means there is always a live conductor directly beside the light feed. Swapping the light feed to one of the outer conductors may solve the problem.

2. Add a neon switch indicator. The neon acts as a path for the voltage to escape.

3. Add a 10k 5w resistor. Either at the switch, or the batten holder.

4. Add a capacitor. Some have reported success with this, though we dont know what size was used.

Non 2 way:

Sometimes cables will be side by side in the ceiling. These can also induce a voltage. Physical seperation may be required.