Shift+Cmd+R and Cmd+R always returning different results? (Chrome and Firefox)

[jasalo]

This is the weirdest error I've had regarding cache. On browsers in which I've previously visited the website, there's some sort of "forced" cache that, no matter how many times I do Cmd+R, it still loads a cached version of an index.html file.

Also, if I do Shift+Cmd+R it correctly loads the new version (on Firefox), but if I do Cmd+R again, it loads the old cached file again!

Weirdest thing is that in Chrome, Shift+Cmd+R ONLY works if the dev console is open. Any ideas as to what can be happening here?

I'm sending a `Cache-Control: no-cache` header which only shows up on the "Shift+Cmd+R" cases. Shouldn't the file be re-cached once Shift+Cmd+R has "correctly" worked (i.e. loaded the new file)?

[sbjs]

I don't understand cache fully, but I do know that if you open Dev Tools in Chrome and long-press the Refresh button, it will give you a drop down with the option "Empty Cache and Hard Reload", and also shows you that Shift+Cmd+R is just Hard Reload without emptying the cache. Sometimes I need to do this, but I don't fully know why or when.