Stellaris dev diary talks about Robot Pop changes in update 1.8
In 1.8 'Čapek' Chattel Slaves, Domestic Servants and non-free Robots have a specific owner that Owner Pop Happiness effects are applied to. : r/ Stellaris
Stellaris: Synthetic Dawn released | Rock Paper Shotgun
Stellaris: Synthetic Dawn and Capek Update Released | Player.One
Patch. 1.8 "Čapek" Notes: What They Actually Mean : r/Stellaris
Dev Team] Čapek update (1.8) Released [checksum 3943] | Paradox Interactive Forums