Haha, I don't think I've experienced that. Boots material are abit thinner but it works well for me.
Whereas for lasinoh, I did experienced a few bags that had hole(s) in it. When I pour in my ebm, immediately I saw my ebm gushing out somewhere. Wasted my ebm! Not many faulty ones though. Say in a pack of 50, I think I've kana 2-3 faulty ones before...
And oh, if my fbm accidentally fell off from my fridge, I do notice that they might get cracked and leaked when I'm thawing them. Or when I tried to break free my frozen
milkbags, I'll also realized that they might cracked if they're strongly stuck together and I used force to break them up.
But probability is not high for my case.