Out of stock product variation without cross

Good afternoon

I appreciate your support: I have been using this plugin for three month and this is really good.

But today I am seeing that for one product, when there is any variation out of stock, this is not showed “Blur with cross” (option selected in configuration) and customer is able to click this (should not been clicked). This is showed like others variations with stock but when customer selects this, below is showed the word: out of stock

This is rare because I have another product with variation and the out of stock variations are showed “blur with cross” and customer cannot click on these (you can see this in next link: https://relajateyteje.com/tienda/lana-copito/). But in the other product that I report, the out of stock variations can be clicked and are not showed “blur with cross” (you can see this in next link, color love#5280: https://relajateyteje.com/tienda/lana-love/)

The only change made recently was to update woocommerce to version 5.5.1

Thanks in advance,