Yes, Israel has transferred US-derived tech to China multiple times, including Python-4 missile components and electro-optics systems, as well as influences from the Lavi program on China's J-10 fighter. The US responded with intense pressure, forcing cancellations like the 2000 Phalcon AWACS deal and leading to resignations. While enforcement has gaps, these incidents underscore the need for strict oversight in alliances, not abandonment—strategic engagement curbs greater threats from Beijing.