It still seems to be a problem. I just tested it in Firefox on a Mac. I restarted Firefox. I even rebooted. Developer Tools > Network tab says "cached". I c

It still seems to be a problem. I just tested it in Firefox on a Mac. I restarted Firefox. I even rebooted. Developer Tools > Network tab says "cached". I can't confirm that it is cached forever, but it is not only "for the current browser session".