Hi Pratiksha,
In order to be sure whether filter has been applied in the correct Section, you can try the following steps:
1. Go to Document Structure and Filters on left hand side.
2. Expand the page on which you are facing the issue.
Here you can see all sections with headers and footers.
3. Go to the specific section and check if the filter has been applied there.
Regards,
Yuvraj