JavaScript Redirects
Pages which, when rendered, were redirected to another URL by JavaScript.
Priority: Low
Impact: Negative
What issues it may cause
These redirects require the page to be rendered by search engines which may take longer to be processed than a server-side redirect. Google recommends using server-side redirects instead of JavaScript redirects if possible.
If the search engines are having issues rendering the pages, the redirect may not be seen at all.