IE Browser Back Button needs 2 click to work

My BACK button on IE browser always needs 2 click to goback to previous page recently. It does bother me much.

Today I found, when I click BACK button at the first time, the page atually goes to htt:/adsecen.sogou.com/. I don't what happened. It looks like only WenxueCity's pages work like this.

Does anyone know how to fix this?

Thanks,