Interesting bug was discovered in Chrome, describing the behaviour of the browser downgrading long-running requests from HTTPS to HTTP after 3 seconds of waiting for a response.
Chrome is cancelling the first request after 3s, then requests the same URL again, this time via HTTP, instead of the original HTTPS.
Chrome downgrading HTTPS to HTTP
Here are the steps to reproduce this issue:
- Open a new incognito window
- Create a new throttling profile in the network tab with settings (1.0 MBit/s, 1.0 MBit/s., 4000 ms) and set it to being used
- With network tab open, go to https://example.com and verify that in some cases, Chrome waits 3 seconds, then downgrades the https request to http://example.com. You might have to try several times.
A bug report had already been filed.
Source: this Stackoverflow post.