Sitemap is generated twice

Question

Mentioned and error in Google search console, saying that there is a problem with sitemap. Further investigation showed that sitemap is generated twice within single sitemap.xml file.

It just repeats everything twice. Tried to disable/enable it, changed all possible options - didn't help.

Moreover, even if I uncheck all options (exclude all urls from sitemap) it still looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
</urlset>
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
</urlset>

Repeats itself from the beginning.

Answer 1

This is one possibility. Plugin might be called twice from the core. Check your optional settings with database tool such as phpMyAdmin.

table : qa_options
field(title) : enabled_plugins
field(content) : Is one "xml-sitemap"?

Comments

There is nothing at all with "xml" or "sitemap" in that table.

I've already found the reason - it is a custom plugin, which will be fixed. When I disable it - everything works fine.