Taiwan Semiconductor Manufacturing Co, the maker of most of the world’s cutting-edge computer chips, discovered last month that one of its chips had ended up precisely where policymakers in the United States did not want it: in a processor made by Huawei.

It is not clear exactly how the chip was routed to Huawei, a Chinese telecommunications firm under US sanctions, but a TSMC customer from China had placed orders with TSMC for a processor with the same design and specifications.