No code was modified , maybe it’s a problem with the plugin super cache or the navigator Internet Explorer.
Anyway, seriously guys you have the best plugin and low cost price for noobs final users who want to create forms with visual UI. but a bug like this one can create for webmasters big problems with their customers when they say to them that they have to buy the plugin for making it work again lol.
If there is a free version for this plugin the “spam buggy verification” have to be optional.