Fixed it with some help, add these steps before opening the new profile:
Step 1: Setting the cookie manually in JS:
document.cookie = key + "=" + value + ";"
return true;
Step 2: Clear local storage in JS:
try {
localStorage.clear();
return true;
} catch (e) {
console.error(e);
return false;
}
And then using Open URL activity to open URL './index3.html?profile=Responsive'
This works, but it should work by just replacing the URL with ‘profile=Responsive’ suffix like Mendix documented. Support is informed :)