Yoast was generating duplicate sitemaps, according to a keen search marketer. It’s unclear how long this has been going on, but Yoast’s head of SEO acknowledged the issue and stated that the company is aware of the issue and working on a fix.
However, after discovering this duplicate sitemap bug, checking other SEO plugins revealed that a similar issue was affecting other plugins as well, though it wasn’t endemic to all SEO plugins.
The Yoast SEO Sitemap Bug was discovered
Brenda Malone (@ brendamalone) found the bug and reported it to Yoast:
@yoast @jonoalderson Is there a way to turn off the duplicate xml sitemaps that Yoast is creating?
— Brenda Malone, Triple-Vaxxed and Still Masking (@_brendamalone) March 21, 2022
page .com/page-sitemap.xml and
page .com/page-sitemap1.xml
Is there a specific reason why these are being created? Thanks.
Yoast responded that they are aware of the issue and have flagged it for internal investigation:
Hey @_brendamalone, the easiest fix for now might be to set up redirect for the '1' version to the plain version (for each post type affected).
— Jono Alderson (@jonoalderson) March 21, 2022
In the meantime, I've definitely seen a ticket in our internal tracker to address this, so I'll see if I can find it and dust it off.
Sitemap Yoast SEO
The Yoast SEO sitemap feature creates a sitemap for each post type automatically.
Page Sitemaps A site with a page sitemap, for example, will publish a sitemap URL that looks like this:
/page-sitemap.xml
Sitemaps should be posted
A post sitemap for a site with fewer than thousands of posts will look like this:
/post-sitemap.xml
Sitemaps that look like this might be published by a site with a lot of posts:
/post-sitemap1.xml /post-sitemap2.xml
Yoast Sitemap Duplicate Bug
Yoast is also generating duplicate sitemaps, according to the findings.
The following sitemaps will be found on a site that only has one sitemap for “pages”:
Original “Page” Sitemap: Yoast “Page” Sitemap: Yoast “Page” Sitemap: Yoast “Page” Sitemap: Yoast “P
/page-sitemap.xml
Duplicate “Page” Sitemaps:
/page-sitemap0.xml /page-sitemap1.xml
Yoast “Post” Sitemap Bug
A site that only has a single sitemap for posts will have the following sitemap:
Original “Post” Sitemap:
/post-sitemap.xml
Duplicate “Post” Sitemaps:
/post-sitemap0.xml /post-sitemap1.xml
Read 15 Fantastic Paid SEO Tools That Are Well Worth the Investment.
Multiple Sitemaps for Posts by Yoast
The bug manifests itself in a different way on a site with multiple sitemaps for posts.
If a site has thousands of posts and three sitemaps are required, the sitemaps might look like this:
Original “Posts” Sitemaps:
/post-sitemap1.xml /post-sitemap2.xml /post-sitemap3.xml
However, as a result of the Yoast sitemap bug, they now have two additional sitemaps that are duplicates of the first.
This is the first sitemap in the example above/post-sitemap1.xml
The following are duplicate sitemaps of the first sitemap:
/post-sitemap.xml /post-sitemap0.xml
On Yoast.com, the Yoast Sitemap Bug is Live
The bug is visible on any site that uses the Yoast SEO WordPress plugin, including Yoast’s website.
These URLs lead to identical Yoast XML sitemaps:
https://yoast.com/post-sitemap.xml https://yoast.com/post-sitemap0.xml https://yoast.com/post-sitemap1.xml
Yoast isn’t the only one with a sitemap bug
What’s even stranger is that the Yoast sitemap bug isn’t exclusive to Yoast.
Many other SEO plugins contain a similar flaw (but not in all of them).
Strangely, a bug in several SEO plugins causes them to behave in the same way.
It’s worth noting that plugin developers are bound by the WordPress open source license, which states that WordPress plugins and themes are considered derivative works. This has been a long-standing issue, which Matt Mullenweg himself clarified in 2015.
Matt wrote:
“WordPress is under a license called the GPL, which basically says you can do whatever you like with the software, but if you distribute changes or create derivative works they also need to be under the GPL. Think of it like a Creative Commons Sharealike license.
In the past people weren’t sure if themes for WordPress were derivative works and needed to be GPL. In 2009 we got an outside legal opinion that cleared up the matter saying that the PHP in themes definitely had to be GPL, and for CSS and images it was optional. Basically everyone in the WP community went fully GPL, sometimes called 100% GPL, for all the files required to run their theme (PHP, JS, CSS, artwork).”
So some approaches to creating a sitemap may be open source and available to all SEO plugin companies to use, which could explain why other SEO plugins have the same or similar bug as Yoast.
Other SEO Plugins are Affected by the Sitemap Bug
Yoast and Rank Math aren’t the only ones affected by this sitemap bug. Other SEO plugins are also affected.
The following SEO Plugins have been confirmed to have this bug:
- Rank Math SEO Plugin
- SEOPress WordPress SEO Plugin
- AllineOneSEO WordPress SEO Plugin
- SEOPress
If your SEOPress sitemap for “posts” starts like this:
/post-sitemap1.xml
Some duplicates are generated on these URLs:
/post-sitemap.xml /post-sitemap0.xml
AllineOneSEO WordPress SEO Plugin
If your AIOSEO plugin generates this URL for the “posts” sitemaps:
/post-sitemap.xml
It also generates these:
/post-sitemap0.xml /post-sitemap1.xml
The above is true for the Rank Math plugin as well.
Bugs in WordPress Sitemaps Aren’t Found Everywhere
Brenda Malone investigated the problem and discovered that some SEO plugins appear to be free of the bug.
The following SEO plugins correctly generate sitemaps:
- SEO Ultimate PRO WordPress Plugin
- SLIM SEO
- Squirrly SEO
What Is the Scale of the Issue?
Making things simple for search engines is the best SEO practice.
The more errors that are introduced, the more likely it is that search engine bots will trip over them, causing unanticipated problems, especially if the problem is compounded by other errors on the site.
SEO stands for search engine optimization. It is better for SEO if you make it easier for search engines to crawl and discover web pages.
Making mistakes is the polar opposite of optimizing. The more errors a website makes, the less optimized it becomes.
In terms of SEO, one could argue that these errors have a minor impact and that the site can continue to limp along and perform normally despite them.
However, errors are still the polar opposite of SEO.
Learn more from SEO and read Google Announces A Search Bug in News Tab.
One Comment