Device goes on/off multiple times

[Peterpc58]

When a device has to go on, it goes on/off multiple times: SK links turned off triggered by service Light: Turn off 2:54:59 PM - 2 minutes ago SK links turned on triggered by service Light: Turn on 2:54:58 PM - 2 minutes ago SK links turned off triggered by service Light: Turn off 2:54:58 PM - 2 minutes ago SK links turned on triggered by service Light: Turn on 2:54:57 PM - 2 minutes ago SK links turned off triggered by service Light: Turn off 2:54:54 PM - 2 minutes ago SK links turned on triggered by service Light: Turn on 2:54:53 PM - 2 minutes ago SK links turned off triggered by service Light: Turn off 2:54:53 PM - 2 minutes ago SK links turned on triggered by service Light: Turn on 2:54:52 PM - 2 minutes ago SK links turned off triggered by service Light: Turn off 2:54:42 PM - 2 minutes ago SK links turned on triggered by service Light: Turn on 2:54:41 PM - 2 minutes ago SK links turned off triggered by service Light: Turn off 2:54:41 PM - 2 minutes ago SK links turned on triggered by service Light: Turn on 2:54:40 PM - 2 minutes ago SK links turned off triggered by service Light: Turn off 2:54:40 PM - 2 minutes ago SK links turned on triggered by service Light: Turn on 2:54:39 PM - 2 minutes ago This happens with multiple lights. How can I avoid this behaviour?