Coupon usage limit has been reached

Back in mid-March, I had an issue were all of my generated coupons were getting error:
Coupon coupon_name was used in another transaction during this checkout, and coupon usage limit is reached. Please remove the coupon and try again.

I found this post that suggested the issue was that the update to WooCommerce added a usage_count field and that all generated coupons would be affected. It suggested adding this function.

add_filter(‘woocommerce_hold_stock_for_checkout’, ‘test_coupon_time’);

function test_coupon_time() {
	return false;
}

Adding this fixed the issue for me at that time. However, I am now getting repeated (but not consistent) complaints that users are getting the following error:

Coupon usage limit has been reached.

When testing myself, I can’t reproduce this error, but reports continue to come in from customers.

I am using
WordPress version 5.4.1
WooCommerce version 4.1.1
WooCommerce Coupon Generator Version 1.1.0

Any help would be much appreciated!

The page I need help with: [log in to see the link]