Firefox isn’t giving me that warning on my desktop, at least. Do you have HTTPS-Only mode on in Firefox security settings, maybe? I used to have that on, but it gave me false security risk errors all the time for some reason (no idea why) for a lot of websites. Especially it’d tell me a site didn’t allow a secure connection/https, but then if I bypassed it and went to the site anyway, sure enough the url would actually show https and the little secure connection lock symbol, so as far as I can tell https is actually working fine.

If you’re on a public network though I suppose interception is also a risk, when you’re logging into things.