It seems you have created a master template for your preference center, which has two layouts:
1) two column layout - which you have set as hidden "display:none", but having the same form id 1025 called there
2) single column layout - which is displayed right now, having 1025 form called again
So when same form is called twice on the same page, it will load twice.
Best solution is to remove the form from the layout which is not enabled, means the 1st layout "two column layout"
Hope this solves the issue.
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