We're sorry to hear about your experience with our Diva electronic low voltage dimmer. The DVELV-300P/303P is rated to control electronic low voltage transformers but using it with LEDs can add additional dimming challenges, so performance issues such as blinking can occur when using LEDs. We would recommend contacting the manufacturer of the under cabinet lights to see if they have a tested dimming that they can recommend as we do not test or evaluate low voltage LEDs with out dimmers
If you have questions or concerns, please reach out to our Customer Support team at leds@lutron.com, or call us 1-844-LUTRON1. We're here 24/7, so please call us any time!
Mike S. @ Lutron Support