Hi Melissa,
for example in pages like this:
eventinapoli.com/eventi/i-verdena-tornan...la-casa-della-musica
Where we need registered users to buy tickets we prompt your login button also in the content.
eventinapoli.com/area-privata (here you can logout)
The browser is Explorer11 but i will try also other browsers and let you know.
In this case we have the SClogin on the left and the login button embedded under the event.
When the problem occours none of the buttons are woring.
In only one occasion i had the sclogin button working but not the login button under the event image.
when the problem occours if i go to a different page with sclogin only (homepage for example), the login has success.
For some reasons the problem is happening randomly. Wondering if it could be related to a caching problem. We use joomla's default caching system.