Wrong product counts in filters (source: attributes)

Hi,
I’m using WooCommerce filters with two mixed methods:
“Destinazioni” is filtered by categories (“Europa”, “Irlanda”, “Spagna”…);
“Catalogo” is filtered by attributes (“Estate Junior 2019”, “Summer Camp 2019”,…).
When I added a new category for “Destinazioni”, the product count got wrong just for the filter “Summer Camp 2019”: it should be 5, but now it shows 1.
The problem is just for the count shown, but the number of products filtered is right.
If I add a new attribute “High School Program” and I add a new product with this attribute, everything turns right.
How is it possible? And how can I solve this problem?
Thank you!

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