Just in case anyone else is looking for this answer in the future – plugin support checked my website and confirmed the issue is with the way the plugin functions and not something they are going to resolve. The plugin strips out HTML tags which includes the WordPress Read More separator, leaving the Read More label behind as plain text.
Thanks for your reply. I am trying to use the Read More feature the way it is designed in WordPress, to control what text is shown as the excerpt. This works, as the correct excerpt is shown, but with the extra “Read more” text. Is this functionality not fully compatible with the plugin? I don’t want to use the shortcode parameter to limit the number of characters as this would apply to all the posts and I only want to change this one. Here are screenshots of the post content in the code editor and visual editor. I have tried turning off the option to hide the excerpt on the full content page but the same extra “Read more” text appears.