A discerning search marketer noticed that Yoast was generating duplicate sitemaps. It’s unclear how long this has been happening, but Yoast’s head of SEO acknowledged the bug, noting that Yoast was aware of the issue and said it was working on a fix.
However, once this duplicate sitemap error was discovered, checking other SEO plugins revealed similar issues occurred with other plugins, but not all SEO plugins have this issue.
Yoast SEO Sitemap Mistakes Discovered
Brenda Malone (@_brendamalone) found the bug and told Yoast on Twitter:
@yoast @jonoalderson Is there a way to turn off duplicate xml sitemaps created by Yoast?
page.com/page-sitemap.xml and
page.com/page-sitemap1.xml
Is there a specific reason to create these? thanks.— Brenda Malone, Triple Vaxxed and Still Masked (@_brendamalone) March 21, 2022
Someone at Yoast responded that they were aware of the bug and flagged it internally to fix it:
Hey @_brendamalonethe easiest fix at the moment is probably to redirect the “1” version to the normal version (for each affected post type).
In the meantime, I did see a ticket in our internal tracker to fix this, so I’ll see if I can find it and wipe it off.
— Jono Alderson (@jonoalderson) March 21, 2022
Yoast SEO Sitemap
The Yoast SEO sitemap feature automatically generates sitemaps for different post types.
Page sitemap
For example, a site with a page sitemap would publish a sitemap URL like this:
/page-sitemap.xml
Publish a sitemap
A website without thousands of posts will have a post sitemap like this:
/post-sitemap.xml
A site with a lot of posts might publish a sitemap that looks like this:
/post-sitemap1.xml /post-sitemap2.xml
Yoast Duplicate Sitemap Error
It turns out that Yoast is also generating duplicate sitemaps.
A site with only one “page” sitemap will have the following sitemap:
Yoast “page” sitemap error
Original “Pages” sitemap:
/page-sitemap.xml
Duplicate “pages” sitemap:
/page-sitemap0.xml /page-sitemap1.xml
Yoast “publish” sitemap error
Sites with only one sitemap for posts will have the following sitemaps:
Original “publish” sitemap:
/post-sitemap.xml
Duplicate “publish” sitemap:
/post-sitemap0.xml /post-sitemap1.xml
Yoast Multiple Sitemap Posts
Sites with multiple sitemaps display the error differently.
For example, if a site has thousands of posts and needs three sitemaps, their sitemap might look like this:
Original “Posts” sitemap:
/post-sitemap1.xml /post-sitemap2.xml /post-sitemap3.xml
But due to a Yoast sitemap bug, they now have two additional sitemaps that are copies of the first sitemap.
So in the example above, this is the first sitemap: /post-sitemap1.xml
These are duplicate sitemaps of the original first sitemap:
/post-sitemap.xml /post-sitemap0.xml
Yoast sitemap bug published on Yoast.com
The error can be seen on any website using the Yoast SEO WordPress plugin, including on Yoast itself.
These URLs point to the same Yoast XML sitemap:
https://yoast.com/post-sitemap.xml https://yoast.com/post-sitemap0.xml https://yoast.com/post-sitemap1.xml
Sitemap errors aren’t limited to Yoast
What’s really weird is that this sitemap bug isn’t limited to Yoast.
Similar errors can be found in many other SEO plugins (but not all).
It’s a little odd that several SEO plugins behave similarly when it comes to bugs.
Something to consider is that plugin makers are bound by the WordPress open source license, which states that WordPress plugins and themes are considered derivative works.This is a long-standing problem Matt Mullenweg clarifies Himself in 2015.
Matt wrote:
“WordPress follows 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 certificate.
In the past people were unsure whether WordPress themes were derivative works and required GPL. In 2009, we got an outside legal opinion that clarified that PHP in a theme must definitely be GPL, while for CSS and images it’s optional. Basically, everyone in the WP community is fully GPL, sometimes called 100% GPL, for all files (PHP, JS, CSS, artwork) needed to run the theme. “
Therefore, some methods of generating sitemaps may themselves be open source and available to all SEO plugin companies, which could explain why other SEO plugins contain the same or similar bugs as Yoast.
Sitemap bug affects other SEO plugins
This sitemap bug doesn’t just affect Yoast and Rank Math. It also affects other SEO plugins.
This bug has been confirmed in the following SEO plugins:
- Rank Math SEO Plugin
- SEOpress WordPress SEO plugin
- AllineOneSEO WordPress SEO Plugin
Search Engine News
If your SEOPress sitemap for “posts” starts like this:
/post-sitemap1.xml
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 sitemap:
/post-sitemap.xml
It also generates these:
/post-sitemap0.xml /post-sitemap1.xml
The same is true for the Rank Math plugin.
WordPress Sitemap Errors Are Not Everywhere
Brenda Malone researched the issue and shared that some SEO plugins don’t seem to contain this bug.
The following SEO plugins correctly generate sitemaps:
- SEO Ultimate PRO WordPress Plugin
- Slim SEO
- Squirrel SEO
How big of a problem is this?
The best practice for SEO is to make it easier for search engines.
The more bugs you introduce, the more likely it is that search engine bots will start stumbling upon the bug and create unforeseen problems, especially if the problem is combined with other bugs on the site.
SEO means search engine optimization. The easier it is for search engines to crawl and discover your pages, the better for SEO.
Error is the opposite of optimization. The more errors a website generates, the less optimized the website is.
When it comes to SEO, an argument can be made to minimize the impact of these errors and say yes, websites can continue to limp and function normally despite them.
But mistakes are still the opposite of SEO.
