We have the same issue with a coupon we’ve had in place since May (unlimited coupon – limit 1 use per user). Recently some users can use the coupon but others receive a “coupon usage limit has been reached” message. The coupon had worked well for over 900 people but now is problematic.
We did upgrade to WooCommerce 3.2.1. Can you please tell me when the next release will be available? We are sending out this coupon daily to people who join our email list and are starting to amass a considerable number of folks who are having difficulty.