Unfortunately this can't be reproduced without a valid login to the site, but I can provide a fiddler session of the requests made by the site if it helps? The page that is blocked is containing javascript with the source below.
Lists Authors need some proof before adding any filter.
Provide a real testable online example... (send the login details to @fanboy / mp3geek @ gmail.com or easylist.subscription @ gmail.com)
•► Read RULES / Use forum Search
••► Don't post clickable links
•••►Upload screenshots at imgbb.com