A ‘bug’ in the popular Yoast SEO plugin for WordPress may have caused websites’ rankings to slip, according to an announcement on Yoast.com.
The bug affected WordPress attachment URLs, which are URLs generated by the popular CMS to display images uploaded by webmasters to their media libraries. Attachment URLs are distinct from image location URLs, which typically live under the /wp-content/ subdirectory.
As attachment URLs typically contain nothing other than an image, a setting in the Yoast SEO plugin allows webmasters to automatically redirect attachment URLs to image location URLs. The stated purpose is to minimize the amount of thin content crawled and indexed by search engines.
According to the announcement, the plugin historically redirected attachment URLs to a post featuring the image served by the attachment URL. However, if an image was featured in more than one post, it became unclear where the attachment URL would redirect to.
The latest version of Yoast SEO – version 7.0 – attempted to deal with this problem by redirecting all attachment URLs to image location URLs rather than a random post containing the image.
When users upgraded from version 7.0 to version 7.0.2, a plugin setting titled “redirect attachment URLs to the attachment itself?”, which allowed users to select either “yes” or “no”, was automatically set to “no”, irrespective whether the user had previously set it to “yes”.
Consequently, the number of URLs generated by some WordPress installations increased by 5x. According to Yoast.com, this created a “Panda-like” problem as Google began noticing a marked increase in the number of thin or superfluous URLs generated by some WordPress installations.
Joost de Valk, one of the plugin’s developers, stated, “The vast majority of the websites running Yoast SEO probably hasn’t suffered at all. Still, we messed up. I myself, am sorry. More so than normal, because I came up with and coded this change myself…”
Yoast SEO discussed the problem with Google’s Senior Webmaster Trends Analyst, John Mueller, who stated, “Sites generally shouldn’t be negatively affected by something like this… if sites are seeing changes, I’d imagine it’s more due to normal search changes than anything like this”.
As a fix for webmasters affected by the problem, Yoast has released a plugin titled “search index purge,” which will generate a 410 status code for each attachment URL. It will also list all attachment URLs in an XML sitemap with post modified dates to encourage Google to recrawl each URL.
The new plugin was released 4 days ago and has been installed more than 2,000 times. According to Yoast, it could take upwards of six months for the attachment URLs to be removed from Google’s index.
Webmasters concerned they may be affected by the update should review the media tab on the plugin’s settings page and ensure attachment URLs are set to redirect. If the setting isn’t configured to redirect attachment URLs, then it’s possible the plugin update is affected by the “bug”.
To date, the post on Yoast has 107 comments from users of the plugin. While the vast majority of commenters appreciate the forthright and transparent approach adopted by Yoast, some users have attributed recent and significant declines in visibility to the bug identified by Yoast.
The owner of Budget Savvy Bride stated, “Honestly, this issue cost me a lot of money. I run a content website that heavily focuses on photos, and my site traffic plummeted to less than a quarter of my normal pageviews as a result. I easily lost $1-2k this month.”