3x 18W led lamp. I tried removing the load but the behavior is the same. The relay might be damaged from the inrush current as there are three switchers starting at the same time.
Yesterday I observed that the output on this channel can change when a blinds motor on another channel stops or starts. The issue is not on the controller side as the channel LED is constantly on. The issue is somewhere on the
AC (switching) side. I am betting on a faulty relay, so I have ordered a few to have on stock (found the specifications on your website - kudos for that).