Rules randomly not loading when visiting site immediately after browser startup
Type: code issue
Hi.
There's a site I use (webdiplomacy.net: rule) that has a working http and https version, but the http version does not redirect on its own to the https version. I noticed that sometimes while visiting this site, I would still be on the http version. When this happens, if I click the https everywhere plugin, it shows no rules for the site.
Through some testing, it appears that when I open my browser, if the first thing I do is go to webdiplomacy.net then the majority of the times it will not redirect me to https. If I wait a bit or first go to another site and then to webdiplomacy.net, it will correctly redirect to https (and list the rule when I click https everywhere.)
I am on linux, firefox 79.0 (64-bit). HTTPS everywhere Version: 2020.8.13. I am able to replicate this with a fresh profile with no changes except https everywhere installed, though I've noticed that on the fresh profile I have to be faster to go to webdiplomacy.net for it not to redirect than I do on my main profile.
The following screenshots were taken minutes apart from the same firefox profile, just by restarting the browser.

The same thing happens with deb.li and I suspect any website that has an https everywhere rule but doesn't do https redirects on its own.
This seems to be a latency issue between first browser open and the rulesets loading.
Duplicate of #17716.