Stream behind the China Firewall Stops Abruptly

We integrated Cloudflare Stream with our site for our videos, intending to be able to deliver to clients that are in China Mainland. We are using customer domains as the latest recommendation to prevent ISP restrictions. We are using iframe solution, so the player is native.

We are getting a report from mainland China that the video we have up is stopping after 8-10 minutes. They tried multiple browsers. What could be the issue and what would be the correct steps to debug the issue further?