I am running Wordpress 4.9.5 and occasionally see the following error in my logs.
E_WARNING: trim() expects parameter 1 to be string, array given
The stack trace looks like this, so it's not coming from custom theme code.
in trim called at /var/www/wordpress/html/wp-includes/class-wp-query.php (736) …::parse_query called at /var/www/wordpress/html/wp-includes/ class-wp-query.php (1621) …ry::get_posts called at /var/www/wordpress/html/wp-includes/ class-wp-query.php (3230) in WP_Query::query called at /var/www/wordpress/html/wp-includes/class-wp.php (599) in WP::query_posts called at /var/www/wordpress/html/wp-includes/class-wp.php (715) in WP::main called at /var/www/wordpress/html/wp-includes/functions.php (960) in wp called at /var/www/wordpress/html/wp-blog-header.php (16) in require called at /var/www/wordpress/html/index.php (17)
Is this a known/unknown Wordpress bug and is there a fix for it?