Firefox Nightly for Android is unable to login to Worlio.
Submitting login credentials does not log in but instead just reloads the form.

Something similar happens with the theme menu. Clicking on a theme and applying it will not save the theme settings.

On desktop, going to the Home page may sometimes log me out instantly regardless of whether or not I have a saved session open. Possibly a local storage/cookies issue of some kind

User agent: Mozilla/5.0 (Linux; Android 6.0; Nexus 5 Build/MRA58N) FxQuantum/100.0 AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Mobile Safari/537.36
Actual browser and OS version: Firefox Nightly 100.0a1, Android 10

I recommend clearing your cookies. Old cookies from the old system may still be in your storage and might cause problems. Also make sure on mobile you are using HTTPS and not HTTP. I noticed it doesn't force HTTPS for some reason when it should. It is being looked into.

Is this still an issue?

The login works now, but as you said previously it still doesn't default to HTTPS.

HTTPS should be forced now.