Page crashes after saving sometimes

For some pages, I get this error.

My temporary fix, is to comment out line 249 of /includes/Elements/Style.php

it seems this line is causing the issue:
$compiled_css .= sprintf( ‘-webkit-box-ordinal-group: %s; -ms-flex-order: %s; order: %s;’, $value + 1, $value, $value );

heres the error on the front end, when wp_debug is enabled

Fatal error: Uncaught Error: Unsupported operand types in /home/aspiesoft/public_html/wp-content/plugins/zionbuilder/includes/Elements/Style.php:249 Stack trace: #0 /home/aspiesoft/public_html/wp-content/plugins/zionbuilder/includes/Elements/Style.php(126): ZionBuilder\Elements\Style::compile_styles(Array) #1 /home/aspiesoft/public_html/wp-content/plugins/zionbuilder/includes/Elements/Style.php(110): ZionBuilder\Elements\Style::handle_pseudo_selector(‘#uid82689457431…’, ‘default’, Array) #2 /home/aspiesoft/public_html/wp-content/plugins/zionbuilder/includes/Elements/Style.php(68): ZionBuilder\Elements\Style::handle_pseudo_selectors(‘#uid82689457431…’, Array) #3 /home/aspiesoft/public_html/wp-content/plugins/zionbuilder/includes/Elements/Style.php(21): ZionBuilder\Elements\Style::get_styles(‘#uid82689457431…’, Array) #4 /home/aspiesoft/public_html/wp-content/plugins/zionbuilder/includes/Elements/Element.php(744): ZionBuilder\Elements\Style::get_css_from_selector(Array, Array) #5 /home/aspiesoft/public_html/wp-content in /home/aspiesoft/public_html/wp-content/plugins/zionbuilder/includes/Elements/Style.php on line 249
There has been a critical error on this website.