If your lights are flickering, it could indicate a driver incompatibility between the bulb and dimmer. 

The executive element in the ZEN27 Dimmer switches is MOSFET, a trailing edge driver. If an LED bulb uses a leading edge driver, this could cause your lights to flicker when turning on/off or dimming.

To resolve the flickering issue, we'd recommend either adding a bypass to the load or trying a ZEN22/ZEN72 dimmer since these models use TRIAC (leading edge).

Please double check that your LED bulbs are also labeled as dimmable. On/off LED bulbs are not compatible with dimmers and will not perform correctly. 

Never use a Z-Wave dimmer with smart bulbs unless you disable paddle control on them first. Dimming smart bulbs from a wall dimmer may damage your equipment.

Please reach out to us if you have any more questions about flickering or compatible bulbs!