Resolved slideshow_full addon was working

Slideshow_full addon was working before sp portfolio update to 1.8. Now it is only visible in front end editor but not in preview. I am using onepage template, Joomla 3.9.18 and SP Page Builder 3.7.2. I have tried removing other modules in case of interference but nothing changes. At first there was a message "Trying to access array offset on value of type bool in..............helix3/core/classes/lessc.inc.php line 632" but it does not appear anymore and neither does the slideshow.