Following Nancy Pelosi's visit to Taiwan, Apple warned Taiwanese suppliers to make sure their shipments comply with a longstanding labeling regulation. The company recently told manufacturers on the island that parts bound for the mainland should list Chinese Taipei or Taiwan as their source.
After tensions with the US flared up following Pelosi's visit, China began to enforce a policy it has had for years. The policy allows officials to reject shipments that claim to be made in Taiwan. There is a set of labeling rules for the island. The point of origin must be listed on shipments.
Apple did not reply right away. Many American companies have a difficult relationship with China. It wouldn't be the first time Apple tried to appease the Chinese Communist Party. Pro-democracy protests in Hong Kong caused the company to remove the Taiwan flag symbol from the mobile operating system.
It is possible that Apple had no choice but to comply with China's policy. Tim Cook said in April that the company's iPad business was affected by shortages of chips. Delays due to a customs dispute would be a disaster for Apple.