Thanks for the reply. There must be some sort of conflict with something. I’ve tried with your version of the plugin and added the filters to my functions but it still doesn’t return anything. Not sure what I’m missing!
You might have some other plugin (or in your own functions.php) that is calling add_filter on the ‘the_content_more_link”. Try changing the priority in the add_filter call to be a larger number (say 99 instead of 16) and see if this solves the problem.
Also, make sure you’re using my version of the plugin. Look at 474 of wp-show-posts.php and make sure it looks like this: