WP Security Scan affects BM Custom Login Plugin

Just installed Security Scan – looked great. Decided to logout for some reason and found that my nicely personalised login page (courtesy of Binary Moon) suddenly had the wordpress logo back – and had resized so that it was all a bit of a mess. Uninstalled Security Plugin and it’s back to normal. What happened?

http://wordpress.org/extend/plugins/wp-security-scan/