Hi @Devidasan Nirmala ,
According to your description, "the portion where we have an embed code (iframe) to embed list" should be a web part.
I can't reproduce your problem, so I suggest doing troubleshooting:
Delete the web part and reload the page to see what happens.
If the problem disappears after deleting it, it is recommended to describe the details of your embedded list when you come back and give feedback.
Thanks,
Yanli Jiang
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