Error appears in Apache error logs

My site is hosted on WPEngine. Recently, the site has started running slow. Before contacting support I checked the error logs and found this and wasn’t sure if this is a theme issue or a plugin issue. Can you provide some insight?

[Wed Jan 20 06:51:54.974760 2016] [:error] [pid 28222] [client 62.210.107.201:56658] WordPress database error You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ” at line 1 for query SELECT u.ID FROM wp_sst_users u INNER JOIN wp_sst_term_relationships r ON u.ID = r.object_id WHERE u.user_status = 0 AND r.term_taxonomy_id =  /* From [www.socialselling.training/members/] in [/nas/content/live/socialselling/wp-content/plugins/sensei-buddypress/includes/bp-sensei-functions.php:117] */ made by require(‘wp-blog-header.php’), require_once(‘wp-includes/template-loader.php’), include(‘/themes/kleo/buddypress.php’), the_content, apply_filters(‘the_content’), call_user_func_array, bp_replace_the_content, apply_filters(‘bp_replace_the_content’), call_user_func_array, BP_Members_Theme_Compat->directory_content, bp_buffer_template_part, bp_get_template_part, bp_locate_template, load_template, require(‘/themes/kleo/buddypress/members/index.php’), do_action(‘bp_members_directory_member_types’), call_user_func_array, BuddyPress_Sensei_Loader->bp_sensei_members_directory, bp_sensei_members_count_by_type, bp_sensei_sql_members_by_type

Thank you for your help!