Coupons are not being applied to a transaction
If your checkout is looking good with a coupon applied but the charge was full price in Stripe take a look at your server caching setup.
- In one case Cloudflare was bringing back an old ?query value back from the cache
- The other thing may need to be done was to exclude the coupons cookie from Varnish on the server
Once that has been corrected go back and re-enable the the server cache and the site cache to make sure they don't interfere.