The filter in place for the US is an automated Javascript challenge that doesn't require any interaction. Yes, it simply lasts for a few seconds before continuing. If It doesn't let you on, it's likely a combination of whatever Javascript version your device is running along with the device itself. So basically a localized problem.
Exactly, in a day or two I'll remove the US filter to see what happens. Luckily this only happens occasionally. It would be great if I could more precisely pinpoint where the problem is coming from. Say a particular state or even the IP address(s). Not just the country as a whole. This way it would cause less of in impact on the normal traffic.
You shouldn't have to close the pop-up to log in as it would be what's called an anchor ad at the bottom. I can't promise anything though due to the plethora of screen sizes, configurations, and devices out there which is understandable.