Hey guys, I made a bundle maker page where the user selects 4 items and it will add to their cart and apply 2 free items of the 4 (handled through the shopify built in discount). the issue is that removing the items from the cart bugs it and the last item can’t be deleted and the cart still considers the price of the 4 items until the user refreshes the page, which then 2- 3 items will be leftover in the cart.
This issue happened ever since I messed with the cart-summary, cart-products, and cart-preview CSS to try and make the cart page more visually appealing. In the console on the live page its giving me these errors. I tried for a day to fix it myself and I just can’t figure out what the issue is. Can somebody please help me? I’m really stuck on this
section-renderer.js:171 Uncaught (in promise) Error: Section header not found at morphSection (section-renderer.js:171:11) at component-cart-items.js:167:9 (anonymous) @ section-renderer.js:171 (anonymous) @ component-cart-items.js:167 Promise.then updateQuantity @ component-cart-items.js:140 onLineItemRemove @ component-cart-items.js:74 #onQuantityChange @ component-cart-items.js:53 (anonymous) @ utilities.js:179 setTimeout (anonymous) @ utilities.js:179 #onQuantityChange @ component-quantity-selector.js:71 decreaseQuantity @ component-quantity-selector.js:34 (anonymous) @ component.js:255 4extension.js:2 WiseReviews version: 1.0.3 section-renderer.js:171 Uncaught (in promise) Error: Section header not found at morphSection (section-renderer.js:171:11) at component-cart-items.js:167:9
Based on the error (Section header not found), it looks like the cart is trying to re-render a section after an item is removed, but it can’t find the expected HTML structure.
Since you mentioned the issue started after modifying the CSS for cart-summary, cart-products, and cart-preview, I’d first check whether any corresponding HTML/Liquid markup was accidentally changed or hidden in a way that interferes with Shopify’s section rendering. CSS alone usually won’t cause this error unless it was accompanied by changes to the theme files.
Could you let us know:
Which Shopify theme you’re using?
Did you only change the CSS, or were any Liquid or JavaScript files edited as well?
Have you tested whether the issue still occurs after temporarily reverting your recent cart-related changes?
Those details should help narrow down the cause and make it easier to identify the fix.
Since this started after your cart edits, it’s likely a cart section markup issue rather than the bundle logic itself. The Section header not found error usually happens when a required section wrapper or data-section-id is missing. I’d compare your edited cart files with the original theme files and restore any missing markup.
This usually points to a theme or app conflict rather than an issue with Shopify itself.
A few things I’d check first:
Open your browser’s Developer Console and see if any JavaScript errors appear when you try to remove an item.
Try previewing an unmodified Shopify theme (like Dawn). If the cart works there, it’s likely something in your current theme or a third-party app causing the problem.
If you’ve recently installed apps that modify the cart (upsells, cart drawers, free shipping bars, bundle apps, etc.), temporarily disable them one at a time and test again.
If the remove button keeps spinning or the quantity doesn’t update, it’s often because a JavaScript error is preventing the cart AJAX request from completing. This is a fairly common symptom when custom cart code or an app conflicts with the theme.
If you can share your store URL (or let us know which theme you’re using), it’ll be much easier to narrow down the exact cause.
The Section header not found error usually means Shopify’s cart JavaScript is trying to update a section after the cart changes, but it can’t find the expected section container in the returned HTML.
Since the issue started after editing the cart, I’d compare your current cart-items, cart-drawer, or related Liquid files with the original theme version—not just the CSS. CSS changes alone normally won’t trigger this error unless a required element has been removed, renamed, or the section structure has changed.
A couple of questions that would help narrow it down:
Which Shopify theme are you using?
Did you edit only CSS, or were any Liquid or JavaScript files changed as well?
If you temporarily restore the original cart files, does the issue disappear?
If you can share your store URL (or a preview link) and the theme name, I’d be happy to help identify which section is causing the rendering error.