The information you provided is true. This is a holdover from quite some time ago, and the previous standard version of WP had an issue that was breaking how Weaver Xtreme wanated to display the continue reading message. But the WP version has changed, and now apparently included additional procession of blocks from the block editor.
This behavior will be removed from the next release of Weaver Xtreme, but I don’t really know when that might be as there are some other issues waiting to be resolved. Probably within a month or so. If you are a bit comfortable with editing PHP files, you could delete everything from line 1145 onward in the Weaver Xtreme theme file wp-content/themes/weaver-xtreme/includes/lib-content.php.