Search bar Flash on page

I hope you are well today and thank you for your question.

This seems happening because the plugin CSS code is taking time to load on your website as your website is heavy to load and takes more time.

You can resolve the issue either by optimizing your website or adding the below CSS code in the Custom CSS option of Ivory Search plugin settings on the path Ivory Search -> Settings -> Settings

.is-menu.dropdown form {
    display: none;
}

Best regards,
Ivory Search Support