Ok, this is really weird... It is working in Incognito only, BUT I'm pretty sure I've cleared everything... I started with specific cookies of the site + a hard reload, didn't work, so then I deleted all cookies + hard reload.. same, finally I selected everything to delete from All time (Cookies data, cache, history, etc), every single checkbox, same issue...
I even tried with a different browser which wasn't even having the extension, I uninstalled a reinstalled and did the same thing, reproducing the same issue, works in Incognito only (of course I gave Incognito permissions to the extension), I have a technical background and this for real.. seems very weird to me... I never had experienced an issue like this before...