Please check your Giant stock composite seatposts on your bike for cracks.
My second stock composite Giant seatpost has now cracked. That makes two cracked on this model in 3 years. You can even see it cracked all the way thru on the inside of the post.
About 1.5 years ago, my stock compsite seatpost cracked. It was replaced under warranty with the same model seatpost.
Today, I was raising this warranty replacement seatpost a little and decided to inspect it just to be safe since the first one had cracked. This one was already cracked worse than the first one. The LBS told me not to ride on it anymore, and they are getting me an aluminum seatpost from Giant to replace it. I am done with the composite/carbon seatpost for this model at this point.
I followed the recommended torque specs and have kept the seatpost clamp oriented how I got it from the factory, and the post still cracked. So, I don't know if this is a recall issue or not. But thought I'd let you know so you don't get any surprises while riding.
Don't get me wrong, I love Giant bikes and my Defy 3. Just this moel seatpost is not working out for me.