I also need to make sure the “Read More Text” value is empty in the WP Show Posts settings. Otherwise, I see the link twice in the WP Show Posts output, one link for the one specified in the WP Show Posts settings panel and once for the text specified in my “the_content_more_link” filter.
This problem does not exist in the GeneratePress Pro theme. There if I override the “read-more” link using the “the_content_more_link” filter and one is specified in the GeneratePress Pro settings panel then I don’t see the link appear twice. Only the one specified in the filter shows up. The one in the Generate Press Pro settings panel is ignored when I override using the “the_content_more_link” filter.