DESCRIPTION
Double post problem willnot occur because of your template but it may occur when youtried to install the 3rd party blog template. When you upload a new template for your blog ,Blogger ask you whether you want to delete these widgets or choose to keep it. This option is useful but the problem arises when the Blog1 widget and Blog2 Widget clashes. Blog1 and Blog2 are post widget so the post will appear double or simply users can see duplicate posts of the original.
SOLUTION
In-order to solve this problem. You have to delete one of the post widgets.
Follow my steps:
Note: Remember to backup your template before editing the code.
1) Go to edit HTML
2) Find the below code
or
3) Just delete the second code
That’s it.I hope your problem is solved