Why is woocommerce not filtering decimal attributes correctly?

Question

WordPress

Hey! At this link the-bootleggers.ru/cat/footwear/mens-shoes there is a product, on the left is a shoe size filter. Shoes, as usual, can have a size of 40 or 40.5, which is taken into account in the store. But none of the existing filters on woocommerce can properly filter the product.
Practice.
Using the link above, try to filter the product by size 40 and notice that in brackets he found 7 units of the product. We click on the size, we get only 3, moreover, all 3 products really have a size 40, but only it, however, the filter also offers to look at another 42 and 42.5 sizes, clicking on which, we generally lose all logic.
I'm afraid this question has been on the 3rd day, I'm not strong in php, but there is a feeling that the filter does not work correctly with decimal values, is this possible?