On both laptop and phone, with two different browsers, my experience is currently:
~20% of pages just load as normal;
~30% I get a "checking you're human" page that resolves and goes the page I want;
~35% I have to click the checkbox to show I'm human and it goes to the page I want;
~15% it says it's verified me (with or without checking the box) but then says a security token is missing and refuses access.

The odd things are:
- after I've just gone through the verification to get to a forum page (eg OMNI /PR), I have to do it again to open the threads from that page;
- if it dumps me after saying "no security token" I can open a new tab and load the same page with no check.

I'm not convinced it's "random to confuse the bad guys" as much as "random because our software sucks."