Why do reviewed issues sometimes reappear?

Summary

Reviewed issues may reappear when changes to a webpage alter the technical markers used to track them across scans, causing previously reviewed or dismissed issues to be treated as new.

Overview

When you review a potential accessibility issue, we make every effort to remember that decision across future scans of your site. However, due to the way websites are built and updated, it's not always possible to persist these decisions over time.

Why it happens

Behind the scenes, Siteimprove uses a system to identify and match issues across different scans of your website. This is based on a combination of technical markers on the page, things like structure, location in the DOM, surrounding content, and other characteristics.

If a new scan finds an issue that matches a previously-reviewed one, your review decision will carry over.

What triggers it

If your website changes, even slightly, those technical markers may change too. These changes may be visually trivial to a human, but semantically significant to an automated system like Siteimprove. So, even if the issue is technically still the same one that was previously reviewed, it may fail to match the old hash and therefore appear as a new issue.

This can happen if:

• The structure of the page shifts (e.g., due to a layout change, CMS update, or content edit)
• HTML tags or classes are added, removed, or rearranged
• Dynamic content loads differently between scans

What to do

When that happens, Siteimprove may no longer be able to confidently match the issue in the new scan with the one you reviewed earlier. As a result, it can appear as a “new” potential issue, even though you’ve seen and reviewed it before.

False positive reports

For issues dismissed as a false positive, all of the above also applies.

On the Activity page, it appears as “No occurrences on any pages match this decision anymore” and will no longer link to a page report.

If you experience this, you may try dismissing using a CSS selector instead.

What this means for you

• This behavior is expected and doesn't mean your review was lost or ignored.
• It reflects the nature of the web, pages are dynamic, and even small changes can disrupt automated issue tracking.
• You can always re-review the issue and mark it again if the situation hasn’t changed.

Key takeaway

Changes to page structure or content can prevent previously reviewed or dismissed issues (including false positives) from being recognized, causing them to reappear as new items in future scans.