woocommerce_cleanup_sessions not working

(woocommerce 3.9.3) For some reason one of our shops is not clearing the sessions correctly. Our customers complain that coupons are “used” when in reality they are stuck in session. I went to look the database and found that there was 151 session rows in woocommerce_sessions table. So then I used the WP Crontrol to trigger the woocommerce_cleanup_sessions which should clear them but it only remove 2 of all 151 sessions. BUT if I use clear customer sessions action from Woocommerce status/tools it clears them away. So whats going on with the cron job not clearing them all?