I have a Sonoff BasicZBR2 relay powering a LED Halloween tree. It works great. The reason for this post is...
Originally I had the LEDs powered by an old Leviton Appliance relay. The tree is not dimmable (or I can't prove it is), I figured a relay output device was the best option. However the Leviton must have some leakage path from input to output because the LEDs would faintly blink on every few seconds.
The Sonoff BasicZBR2 does NOT cause the LED to blink, when the relay is off the LEDs are completely off.