Delamination is just carbon fiber composites main mode of failure. As long as the material you use is rated for its stress life it's fine. Buying expired material means the resin was decomposing, making the carbon fiber composite more prone to failure.

All materials eventually fail, some have endurance limits with infinite stress lives, like most steels. Some don't, like aluminum. Without knowing the details of their design there's not an easy way to say whether carbon fiber was even a bad choice at all. But buying expired carbon fiber absolutely is a bad idea for anything critical.

The stress life curves for carbon fibers vary a lot, they certainly won't be as nice or long lasting as most metal alternatives, but that just means more replacement or maintenance, something a luxury submarine doesn't necessarily care about as much.