Site Navigation Templates can only be successfully applied to Sites where you are not currently logged in.
To apply the Template to the desired Site:
Navigate to a different site on the enterprise
Go to Enterprise on the Navigation Bar
Select Manage Sites
Select the desired Site Navigation Type from the drop-down menu
Select the site where you want to apply a Site Navigation Template
Click Apply Template
"Are you sure you want to create new Navigation bar for all selected sites?"; Click Yes
"New Navigation bar has been successfully set." Click OK
When you switch back into “Site A”, the Navigation Bar will match the template.