When a Servo Bot is considered a Household NPC or otherwise uncontrolled through Control Any Sim, their "Servo..." dialogue option will be unavailable. Hopefully this is something you are able to do something about, and is not hard-baked into the game.

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P.S:
I usually don't report "bugs" for mods as stable and popular as CAS is, but it is essential to my Sims gameplay.
Thank you for your work!