Thanks Jon... for both the useful references and the fast iteration. I'll be sure to dive into those books in time.
Meanwhile, this error may disappear with the new version of the plugin, but I wanted to let you know that the login page also got the auto-appended 'keyword=value' string, rendering me unable to login without clearing my history/cookie, or doing so in a private/incognito window.
Here's how the URL looks like when that happens:
http://theastro.staging.wpengine.com/wp-login.php?wpe-login=theastro&_jr_mt_theme=jc-sbetr-puvyq
Glad you found out what went wrong, and I look forward to check out the new version with JS approach.
p.s. sorry for not responding earlier yesterday, our nation was fully absorbed with the presidential election race: http://www.todayonline.com/world/asia/indon-stalemate-both-sides-claim-victory?singlepage=true