I have stuff on R2, I don't personally use Jio, and the office has multiple ISPs but not Jio. Customers had randomly complained that some of the icons were broken/some files could not accessed, but never followed up our request for browser console/network snapshots, and our testing always showed everything working fine (we were very small with a handful of customers, at the time).

Finally, purely by chance, office network was having issues, so one of my QA people switched to their mobile hotspot, and they were on Jio. And then they could see all the broken stuff, but weren't sure why. Stuff escalated to me, and it finally clicked!

Easy to work-around by using a custom domain, though painful if you want to do access control/signed urls/etc as CF still only supports them on the r2.cloudflare urls. Had to put a worker in front.