It has been belatedly revealed that South Korean counterintelligence and defense agencies detected and intercepted attempts by India and Taiwan to illicitly acquire South Korea’s core submarine technology approximately three years ago.
Folks will be shocked by this, but spying among allies - particularly for advanced technology - is incredibly normal and common.
A great deal of modern US technology is pilfered from allies. A great deal of Israeli and Saudi and German technology has been pilfered.