Hey David,
Sorry for the delayed reply, there was an issue where all my WP.org notices were going to the SPAM folder and I was unaware.
I’m looking at the “one position” example but I don’t see any “categories list” on the sidebar but I see a list of what could be categories beneath the title, such as “Hledané pozice” and when I click it goes the the archive just fine (no 404) but if I click on a different one it does 404 such as this one Marketing.
Now, these are just standard WordPress category archives, so my plugin wouldn’t affect these at all. If you are getting these errors it’s going to be outside the scope of the Post Types Unlimited plugin (you can always de-activate the plugin and refresh the archive to confirm if you wish).
It looks like you’ve created custom URL’s for your categories so they aren’t using the standard WordPress slugs. When visiting one of the archives the slugs look something like this “/category/pracovni-pozice/hledane-pozice/marketing/” – so you’ve added “pracovni-pozice/hledane-pozice/” to the slug – I don’t know how you’ve added this, but I suspect it was done either via custom code or via the WordPress permalinks dashboard. In which case there may be a conflict or you need to register new rewrite rules on your site for these custom slugs to work – https://developer.www.ads-software.com/reference/functions/add_rewrite_rule/
An easy test would be to set the WordPress permalinks to the default structure to verify everything is working correctly and the issue doesn’t lie elsewhere. If setting your permalink structure to the WP default doesn’t fix the issue then you may need to try disabling plugins and/or your child theme to see where the error lies.
I would also recommend not using the standard categories for custom post type taxonomies unless you want your standard posts and custom posts to be in the same archives. If these post types are to be separate then you really should be create a custom taxonomy (eg: pozice_category) for your post type – this way everything is separate and better organized.
Unfortunately permalink/404 errors are outside the scope of the plugin so there is little assistance I can provide but hopefully my advice helps you locate the problem!