Domain isolation: ports, toggle
Some file hosts use different ports to download, apparently causing the browser to change circuit, breaking the download. For example, http://l2.lumload.com:182/d/zaoqtg3g4dnnofoc5r5djliistfo6e2omqdecblg7j7ghqshhk5ikio7/dictionaries.7z Happens on 4.5.2 and 4.5.1. On 4.5, the sites work sometimes, usually after creating new circuit.
Steps: try downloading lumload.com/zi9eiamfbz3x Press free download Wait and solve captcha (change circuit if captcha error) Press download "Wrong IP"
Even if it is because of the port, isolation should be a toggle.