/category/ and /tag/ nonexistent redirect to a random post instead of 404
My site is redirecting links of /category/ and /tag/ that don’t exist, for example /category/asdasdasd123/, to a random post. That always redirected to the same post yesterday, but today it changed to a different one.
I have tried disabling some redirect plugins and nothing changed. I am using apache and the htaccess is the default. With categories that exist it shows perfectly. The category and tag base option is empty. My version is 4.9.13. Any ideas?