Tried the tutorial, doesn’t change anything work.
I wrote my own plugin that replaces content and it still works, and no its not my plugin messing them up, I disabled it and even totally removed it to make sure.
I use add_filter(‘the_content’) as the trigger but as far as I can tell these other plugins don’t use that trigger, I haven’t looked into how they work but since its more than one plugin I would assume its not the plugin but something in WP that changed.
I haven’t tried a fresh WP install, maybe it has something to do with the upgrade?