Hi Giacomo,
I suppose that it’s not a bug, but a feature.
Look at ‘Settings->User Role Editor->Additional Modules’ tab, ‘Content Edit Restrictgions’ section. Do you have ‘Activate “Create” capability for posts/pages/custom post types’ option turned ON there?
Did you test with ‘administrator’ role of with any other one?
If ‘Yes’ on both questions, then check that ‘create_act_templates’ capability was granted to that role too.
