Does AMP validation error affect SEO result?

Or the question should be: what are the impacts of the AMP validation errors?

My client team uses AMP and they hope to implement JS tag directly onto the AMP pages without <amp-script> tag (Cause the target JS lib won't work in web worker environment).

So I'd like to know the impacts of including the <script> tag.

Plus: Sincerely hope it doesn't affect the Google search ranking.

Does AMP validation error affect SEO result?

Funny question 😉 If Google stops displaying your amp pages in search results, do you think this will affect SEO or not?

1). Let's start over. Did you know that amp pages are displayed in Google search on mobile devices with a special icon? For example:

In other words, Google marks such pages as AMP. This is not only an icon, but a number of features also appear here. For example, Google AMP Cache is used for these pages, which speeds up the page loading speed, and they also use their own structured data(schema). Here is an example, a markup option for Article: https://developers.google.com/search/docs/data-types/article - as you can see, the markup for AMP pages differs from the usual ones.

2). If your AMP pages are not valid, Google will no longer display them as AMP pages in the search, so you will lose all the advantages of AMP pages in Google search. More detailed: docs

3). If Google stops displaying your AMP pages in the search, it will continue to display regular pages in the search. This is more complicated and requires more information about the project. Usually AMP pages are created as an additional version to the main version of pages, but sometimes only the AMP version exists.