The TBMs were designed by a German company, Herrenknecht, but those particular machines were manufactured/assembled at Herrenknecht's facility in China. When they were ready to be shipped from China to India, Chinese customs clearance delayed their export purposefully. Herrenknecht itself said it was facing “extraordinary circumstances” with Chinese customs clearances.
A lot of international relations is ultimately driven by strategic interests and political relationships. Countries often adjust their trade policies, technology transfers, export controls and cooperation depending on their relationship with the other country. What is acceptable with one partner may be restricted with another. That's simply how geopolitics often works. another way to say - dirty international politics,