Many LightWave switches/dimmers require lamps that are compatible. In some cases of incompatible lamps the use of a Neutral will improve ( or enable ) the operation of the switch/dimmer.
When the Neutral is not provided to the switch/dimmer then there has to be enough current leakage through the lamp when OFF to power the electronics in the switch/dimmer.
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This may be because the lamps on the circuit are not compatible. First, check that the lamps are dimmable variants if they are LEDs. If the circuit load is low (i.e. <10W) try increasing the circuit load by changing or adding lamps (bulbs). Where possible, adding a neutral wire to the Dimmer will increase compatibility. Compatibility charts displaying Lightwave tested and approved LED lamps are available on lightwaverf.com.