Parent Category Counts show double

When I turn on the option “Show post count” in the plugin setting, the post counts in parent categories show doubled number of actual counts.

Let’s say I have “5” posts that are set to “Sub A”, the parent category “Par A” show “10”.
There is no posts that are set to “Par A”. (I don’t use any parent categories to categorize posts.)
The count of parent category must show the total counts of posts in sub categories, but it is not.

Does anyone have ideas why it happens?

My environment is below.

WordPress: 5.4.2
Collapsing Categories: 2.2.6

Also, I am using WooCommerce and using “Collapsing Categories” plugin to show categories of WooCommerce products.

Thanks,