Amasty Shopby V2.22.0 behavior differs greatly from V.3.2.2 on filterable attribute

Amasty Shopby V2.22.0 behavior differs greatly from V.3.2.2 on filterable attribute

Hi, I just update our Amasty Shopby module from V2.22.0 to V.3.2.2. I found that in V.3.2.2 some filter is showing while it's not in V2.22.0.

For example we have x number of products that use either car-seat attribute set or crib attribute set. Those product will shown in the search result (./catalogsearch/result/index/) when user input some keyword. In the crib attribute set, we have an attribute that doesn't exist in car-seat attribute set called "is_bag_included". In this example all product that has "is_bag_included" attribute, has them set to "No".

In V.3.2.2, "is_bag_included" filter is shown, while in V2.22.0, the filter is not shown.

So my question are:
1. Why the behavior change happens?
2. Which is the expected behavior from the module design perspective?
3. If I want to make the "is_bag_included" filter hidden in V.3.2.2 as in V.2.22.0, what should I do?