I had a web app that was making perhaps an unreasonable number of concurrent requests. Every now and then, pretty regularly like 1 in every 20 full page reloads

I had a web app that was making perhaps an unreasonable number of concurrent requests. Every now and then, pretty regularly like 1 in every 20 full page reloads it would fail somewhere along the line. I switched from the lib I was using to XMLHttpRequest directly and it worked reliably with little in the way of cluttering the code as I made my own minimal wrapper without the features I didn't need from the lib. That was quite a long time ago and the lib has likely had whatever the problem was resolved.