Design/robots specifications and filter extensions
Separate layered navigation filters from sorting and tracking. Individual important filter targets need a consciously defined role instead of a blanket parameter treatment.
Compare the default for search engines in the effective store area with additional rules of layered navigation or SEO extension. An inherited setting can affect multiple store views.
Where to check the setting in Magento
Under Content → Design → Configuration, check the affected Store View and its Search Engine Robots. After that, compare additional rules of filter or SEO extensions. A basic setting adopted from the test shop can affect all pages.
Example of this specific finding
Illustrative control case: /shoes/? color=red shows a purposefully maintained red shoe collection; /shoes/? utm_source=newsletter shows unchanged content. Both types of parameters require different decisions.
follow-up audit in Magento
Retrieve product, category and filtered view for each affected store view. First determine which page type should be consciously excluded.
For each parameter function, specify whether a useful search entry is created. Adapt internal links, sitemap, canonical and, if applicable, exclusions to this decision.
Derogations and scope
Indexable parameters are not fundamentally flawed. A blanket block can exclude independent filter landing pages from the search.
Reference: Magento Open Source or Adobe Commerce with classic storefront. Consider store views and extensions; other storefront architectures have their own configurations.
Classify the general error
Definition, system-independent causes and further correction examples: Evaluate parameters by function
Configuration and test signal documentation
Adobe Commerce: Page Configuration and Robots Specifications