+1 On the fork bulging or splitting because of top cap over-expansion. This has nothing to do and is a common enough user error that some makers have changed to a glued in steel sleeve and a star nut that eliminates user discretion there. You definitely need a new fork, lest the split steerer snaps off when you work the bars during a sprint or hill climb.

Unless your fork is on a recall list, you're at the mercy of Giant's generosity. IMO splitting of a steerer from top cap over expansion is a user error not a fork defect. You may try your luck with Giant, but don't blame them if they say no. However if they do say no, you may try for a hard luck discount. When I handled warranties, I always tried to find a way to give a break in cases where I couldn't (or wouldn't) warranty something. Usually it was an option to purchase a replacement at a deep discount.

BTW- while some makers specify a top nut torque, I'm not a fan of the concept. The optimum preload depends on the type of headset bearing and angle of contact. As noted it varies by a factor of 5 times depending on brand or model. No mechanic can remember that many specs, and there's too much between the top cap and bearing that can introduce variables for this to offer any degree of reliability.

Leave the torque wrench on the bench and tighten headsets sufficiently to remove all free play, measured by the front brake test. Cross check that the steering is free. If not sure check by walking bike holding the seat. The bike should steer easily with only slight changes in angle. Headsets need very little (if any) preload because all the flex in the system only tends to increase load anyway. They clearly announce looseness with vibration when braking, or with a knocking sound on rough roads, so an attentive rider can easily detect and correct a loose headset.