Between my Thomson post and the carbon one they gave me, even at 6-8nm, I can still rotate the seatpost in the frame. Cleaned both well, carbon paste on both seat posts, same result. I could increase the torque and I bet I still have the same issues…
Welcome to my world with the 177 seatpost clamp issue.
I currently run a cheap (relatively heavy) alloy 27.2mm seatpost with fiberglass tape wrapped 2 layers inside the seat tube / seatpost / clamp interface. Also changed the clamp bolt to a 30mm hex socket cap bolt and fastened the bolt pretty tight.
Now no rotating or slipping for over 500km of riding. Still have my eyes on it, watching the slide mark closely. No slip yet so far.
The carbon seatpost that came with the frame has two deep clamp scratches from slipping. Not safe to use anymore.
I'll be leaving the 177 on the indoor trainer forever when my 099 zero offset seatpost arrives.