As with faulty sockets, many of the same reasons apply as to why a light may be faulty or flickering.
Of course, sometimes just the bulb is to blame. Occasionally when LED bulbs begin to fail they will flash intermittently once or twice within a second and this will repeat every 1-20 seconds. Generally, the consumer can resolve the issue by simply replacing the bulb. When buying new bulbs, especially if changing halogen bulbs to LED’s, make sure that if you have a dimmer switch on the circuit, that the replacement bulbs are compatible and dimmable. Most standard bulbs are fine to use but you may also find some dimmers are not able to dim LED’s and this could cause further problems.