Filter stock amount in “single variations”

Ok, here is the case :

I have 3 different T-Shirts / W different print (In 3 different colors , Blue, Red & Green) they come in 3 different sizes (S, M & L)

The first Tshirt, (Blue) I only have in S, the Red T-shirt, only one in medium and the Green i only have one left in L..

Now , here is the issue:

So I’m using the built-in search-filter-nav in Woocommerce and when i choose filter by size > S < all i want, is to see only T-shirts available in S – Logically this should only display Blue T-shirt which only has one in S.

but the filter shows ALL T-shirt colors (Because they all have Single variations of S M & L. I have checked the checkbox “Hide items with zero stock” in Woo settings, but the filtering is not working at all.

In shop category page filter says: S (3) M (3) L (3)

In Shop-settings , I have set Single variations to Blue Tshirt S=5, M=0, L=0 , Red Tshirt S=0, M=5, L=0, Green Tshirt S=0, M=0, L=5
The stock control is set on “Single variations” level