I started freezing milk in the first pandemic, as I needed to buy enough in my online shop to see me through to the next available delivery. As the slots were as rare as hens' teeth, that often meant buying enough milk to last us three weeks, so freezing was the only option.
To begin with, thawing the milk was no problem (though it's a bit 'weaker' after - we see the difference in the colour of tea and coffee drinks).
Then we had a couple of months when the plastic cartons were nearly all splitting when frozen. Tesco must have changed supplier, I think.
Luckily, that problem ended as suddenly as it had begun, but we always stand or lay the bottles in a larger container to thaw now, just in case.