Faq Why the Google Search Console reports AMP validation errors even after they have been fixed?
Why the Google Search Console reports AMP validation errors even after they have been fixed?

If you have validation errors about your AMP pages, the Google Search Console/Webmasters Tools will be likely to advise you by email and you will see these errors listed in the AMP pages section.

In such case the first thing to do is to check if the configuration is correct and to take advantages of JAmp settings to exclude HTML tags, attributes, etc that are responsible of invalidating your AMP pages.

After that you have fixed AMP issues, you may expect to see errors in Google Search Console/Webmasters Tools immediately gone, but unfortunately that's not the case. Always execute and rely on the AMP test https://search.google.com/test/amp to ensure that AMP pages are valid and have no issues.

Indeed even after that AMP errors have been solved, Google Webmasters tools/Search Console will continue to show errors just like before as a report for errors history. Errors in the report history will be shown at least for 90 days or even never removed although marked as fixed or having 0 pages affected, see Google documentation for more info: https://support.google.com/webmasters/answer/7450883?hl=en

The Google Webmasters tools/Search Console requires a lot of weeks to refresh and commonly it continues to show previous errors even if they have been fixed just to have the chronological history of found and fixed errors.

If you are using the new Google Search Console, notice that Google added a feature to speed up re-validation of AMP pages.

You can ask Google to re-validate your AMP pages clicking on the 'Validate fix' button and starting the process of a new validation. The Google Search Console send you an email to confirm that the validation has been started.

After some days you should receive another email to confirm that issues have been fixed or not; even in the case that you receive the confirmation that issues have been fixed do not expect to see them disappear quickly from the Google Search Console. Errors will still be there but the number of pages affected should be decreased and reported as 0 zero. After several weeks/months probably the Google Search Console will definitely refresh and all past errors won't be shown anymore.

Probably this report will be fixed better in the future when the new Google Search Console will reach a more stable stage.

In the old Webmasters Tools AMP errors could be synced with the new Google Search Console and removed definitely after several weeks.

After that the re-validation has been completed, fixed errors will still be counted even if marked as fixed in the validation column. This is a kind of bug of the new Google Search Console that will be hopefully fixed in a more stable release, being now a false positive.

The report below has indeed no more errors, being 2 errors re-validated and flagged as 'Looking good' and another error now counting 0 pages.