Product categories display incorrectly

Hello,
site: https://casaecolori.it/
I’m facing an issue with product category archives.

Issue description
I have a parent category:
Vernici & Smalti
with the following subcategories:
Stucci e Collanti
Pitture per Interni
Pitture per Esterni
Pitture Decorative
Smalti
Vernici per Ferro

All subcategories:
contain products, have correct parent–child hierarchy, have category thumbnails, show correct product count in WooCommerce admin.
However:
only one subcategory (“Pitture per Interni”) displays products correctly all other subcategories load as empty pages (no products shown)

Example URLs

Working subcategory:
https://casaecolori.it/product-category/vernici/pitture-per-interni/

Not working subcategories (examples):
https://casaecolori.it/product-category/vernici/stucchi-e-collanti/
https://casaecolori.it/product-category/vernici/pitture-per-esterni/
https://casaecolori.it/product-category/vernici/pitture-decorative/
https://casaecolori.it/product-category/vernici/smalti/
https://casaecolori.it/product-category/vernici/vernice-per-ferro/

All categories:
display type set to Default
correct parent category
thumbnail image assigned

Catalog Mode is disabled
Cache cleared (plugin + browser)
Products are assigned directly to subcategories

Request
Could you please solve my problems:
You can disable the plugin or plugins that might be preventing categories and subcategories from displaying correctly. However, I think the reason is different.
Thank you in advance for your support.

Hello,

I have checked your subcategory pages, and the products are showing fine.

See Screenshot for clarification: https://ibb.co/vCSKZwqG

Please clear your site cache, browser cache, and check the site in incognito mode / another browser to confirm if the issue persists.

Best Regards,

Yes, thank you. I disabled the plugins—the display is working now. Thank you!

Some product subcategories have started to display correctly, however several categories are still not loading properly.

Current behavior:
For some product categories/subcategories, the page loads with header and menu, but the content area is completely blank (no products, no layout).
Other categories work correctly.

The issue is inconsistent and affects only certain category URLs.
https://casaecolori.it/product-category/vernice-per-legno/impregnante-per-legno/
https://casaecolori.it/product-category/vernice-per-legno/smalto-allacqua-per-legno/
https://casaecolori.it/product-category/vernice-per-legno/vervice-per-legno-esterno/
https://casaecolori.it/product-category/vernice-per-legno/vervice-per-legno-interno/
https://casaecolori.it/product-category/vernice-per-legno/accessori-vernice-per-legno/

I am attaching the affected links for your review.

What has already been done:
Cache and optimization plugins were tested and cleared.
WP Rocket is currently disabled.
The issue persists even without cache.
Homepage works correctly – but lowly (very ,owly).

Some categories work, others do not.

Please advise:
What could be causing only certain product category pages to display blank content?
Is this related to WoodMart product archive templates, category settings, or theme configuration?
What exact steps should I take to resolve this issue?

You may disable any plugins you consider necessary for debugging purposes — this is not a problem for me.

I would really appreciate your help in resolving this issue.

Thank you in advance.

[Author]

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