The original multi-collection post covers the general shape of the smallest-collection-wins rule. A small Sale collection sitting alongside a larger category tree is a situation where the rule picks the wrong collection, and there are three ways to fix it today.
The setup
You have a clean category tree:
- Men’s
- Shirts
- T-Shirts (200 products)
- Shirts
You also have a sitewide Sale collection (40 products), and some of your Men’s T-Shirts are on sale. So a sale T-Shirt is in two collections: T-Shirts and Sale.
A customer lands on the product via a short-form URL, say from Shopify search, or a marketing email link, or Google. Which breadcrumb should appear?
What the default does
The default disambiguation rule is Most specific (smallest collection) breadcrumb, the leastprod option of the Breadcrumb selection on product pages setting in the Theme Editor. For most products, that picks the correct leaf category, exactly what the original post recommends.
But: Sale has 40 products. T-Shirts has 200. So most specific picks Sale, and your customer sees Home > Sale instead of Home > Men's > Shirts > T-Shirts.
Almost every store has a Sale collection that’s smaller than its main category leaves, so this version of the multi-collection situation turns up wherever the smallest-collection-wins rule is enabled.
What works today
1. Use a dedicated Categories menu (recommended)
Create a second menu in Shopify (Online Store > Navigation) called something like Categories, and only put your taxonomy in it - your category leaves (T-Shirts, Shoes, Hats) and the parents above them. Crucially, leave the marketing collections out: no Sale, no Featured, no New In.
Then in Breadcrumbs Uncomplicated, set Top-level category to that new menu. The post on Switching which menu drives your breadcrumbs walks through where the setting is.
Sale isn’t in the Categories menu, so the app doesn’t consider it when picking a breadcrumb. A sale T-shirt’s trail walks the taxonomy and finds Home > Men's > Shirts > T-Shirts. This is the cleanest setup for most stores: a one-time change, works for both short-form and long-form URLs, no per-product work, no theme tweaks.
2. Set a Default Collection Reference per product
For specific products where the auto-pick is still wrong (e.g., a hero product you want pinned to a particular collection), set the per-product custom.default_collection_reference metafield to your preferred collection. That override beats every other rule.
It’s reliable but manual: it has to be applied to every product where you want to pin the breadcrumb. Practical as a top-up for a handful of products; impractical as a whole-store fix.
3. Use long-form URLs everywhere
If your theme creates long-form /collections/.../products/... URLs, the disambiguation rule doesn’t get a chance to pick anything: the URL itself tells the app which collection to use.
The app’s Fix short-form URLs for products linked from collection pages setting (the Short-link fix) rewrites in-collection product links to long-form on the client side. See the original post’s Short-link fix section. Long-form URLs straight from your theme are preferable where you can get them; the short-link fix is a JavaScript rewrite and only helps for navigation from a collection page (not from search, marketing emails, or external sites).
Which collections cause this?
The pattern: any collection that cuts across your category tree rather than sitting inside it. In most stores, that’s the marketing collections. Common candidates:
- Sale / On Sale / Clearance
- New In / New Arrivals
- Featured / Staff Picks
- Best Sellers
- Gift Guides
- Anything tagged “All” (e.g., your auto-generated full-catalog collection)
If you’re using the dedicated-Categories-menu approach from fix 1, none of these should be in that menu.
What about Sale-only shoppers?
If a customer arrives via your /collections/sale page and clicks a product, won’t they want to see Home > Sale as the breadcrumb?
Yes, and they will, because the long-form URL /collections/sale/products/x overrides disambiguation entirely. Disambiguation only runs for short-form URLs (/products/x) where the app has to guess which collection the customer came from.
Summary
The default Most specific (smallest collection) breadcrumb is the right rule for almost everything, but it picks the wrong collection when a small Sale collection sits alongside a larger taxonomy. For most stores the cleanest fix is a dedicated Categories menu with no marketing collections in it, set as your Top-level category. Per-product overrides and long-form URLs are alternatives that work too.