Is it possible to do a k-turn with a phantom during the activation phase, and cloak using the advanced cloaking device after attacking during the combat phase in the same round?

Depends on whether you've got something to remove the stress

Advanced Cloaking Device grants a free cloak action and you can't take actions while you're stressed. So if you have a stress token, it does nothing for you. The where it came from or how long it's been there doesn't matter. Similarly, if you can do something to avoid the stress, or remove it before the ACD triggers - Yorr, Wingman, Adrenaline Rush, etc - you'll be able to recloak just fine.

You would have to get rid of the stress from the k-turn somehow. Using Yorr to syphon it off as it happens or a wingman to vanish it at the start of the combat phase both sound like good aporoaches.

You cannot perform an action while you have a stress token though, so if you cannot get rid of the token before ACD triggers you cannot perform the cloak action.

Bah!! Ninja'd.

Thank you