This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Just the addition of that tag will have no effect on the HTML and therefore the layout of the page. However, is there code later in the page that does something differently based upon the setting of that scoped variable?
Also, have you compared the rendered HTML in each case to see what has changed? That could give you a clue to the cause of the issue.