Push pending requests via new requests

I have implemented tus protocol for large video uploads: it divides a video to chunks and sends them assynchronously to the server. The web application is proxied through Cloudflare .

The problem is, requests periodically stop (shows ‘pending’ in Network ) for a long time (until timeout). And the way to resume upload is bizarre: dublicate the web url in another tab of the browser. Requests of new tab somehow push the pending requests (I see both of them in same Network ) and upload continues!

Tested multiple times on Chrome and Edge.