Titles issues

I did a style change on a page title from my free MagnusWP template and after that every time I change a title, all page titles are changed to that one.
I uninstalled the template and reinstalled it, but the problem persists. I even deleted the entire template folder from the hosting, but nothing, the problem persists.
I will appreciate if someone can guide me.

The page I need help with: [log in to see the link]