Turn a Support Thread into a Bug Report

Title
Checkout spinner never stops after applying promo code COFFEE10 on iOS Safari

Steps to reproduce
1. On an iPhone running iOS 18, open Safari and navigate to the storefront (customer used the site’s checkout).  
2. Add two bags to the shopping cart.  
3. Go to Checkout.  
4. Enter promo code "COFFEE10" and tap Apply.  
5. Observe the checkout spinner/loading indicator.

Expected result
- The spinner stops after the coupon is applied (or a validation error is shown).  
- The order total updates to reflect the discount (or a clear failure message is shown).  
- Customer can proceed and complete checkout.

Actual result
- The checkout spinner continues indefinitely after applying COFFEE10, blocking checkout.  
- Without applying the code, checkout works normally.

Environment
- Browser: Safari (mobile)  
- Device: iPhone  
- OS: iOS 18 (support reproduced)  
- Cart contents: two bags  
- Reported by customer; issue reproduced by support on iOS 18

Missing information
- Exact storefront URL / site environment (production/staging).  
- Whether the customer was logged in or checking out as guest.  
- Exact product SKUs/IDs for the two bags.  
- Whether COFFEE10 is valid for those items (coupon rules: percent/amount, minimums, product/category restrictions, expiration).  
- Whether the issue occurs on other browsers (Chrome/Firefox) or desktop.  
- Whether the issue occurs on other iOS versions or earlier/later Safari builds.  
- Any client-side console errors, network logs (failed XHRs), or server-side errors correlated with the failure (stack traces, request IDs).  
- Whether any error or failure message ever appears (hidden behind spinner).  
- Whether retrying Apply, removing items, or changing quantities unblocks the spinner.  
- Whether the problem occurs for other promo codes or only COFFEE10.  
- Network conditions during reproduction (Wi‑Fi vs cellular).  
- Whether reproduction was on a physical device or simulator.  
- Session/cart identifiers or timestamps to find relevant server logs.

Suggested next actions
- Capture browser console and network trace while reproducing (Safari remote Web Inspector).  
- Check server logs around the timestamp and session ID for coupon validation requests.  
- Verify coupon configuration and eligibility rules for COFFEE10.  
- Try reproducing on other browsers/OS versions to scope impact.