error_log in wp-admin folder

My setup:

PHP 5.4.
WordPress version 4.1.
EWWW Image Optimizer version 2.2.2.

Everytime I go to Settings > EWWW Image Optimizer, there will be an error log in public_html/wp-admin/error_log with the following information:

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 ‘-1000’ at line 1 for query SELECT orig_size-image_size FROM xxxxx_ewwwio_images LIMIT 1000, -1000 made by do_action(‘wp_ajax_ewww_savings_loop’), call_user_func_array, ewww_image_optimizer_savings_loop

Please help I’m not sure is this just happen to me? Thanks.

https://ww.wp.xz.cn/plugins/ewww-image-optimizer/