I wonder if this happens if the tyre gets frozen, some of you live in places where it snows. Hedgehog might be a good person to ask as I recall he rode his bike in all sorts of low temperatures....
Motorcycle tires hold up just fine in Winter (if inflated properly...), although they usually don't have as much traction as in warmer temperatures. Outgassing causes dry rot (cracking).The second picture is of the new tire that I just purchased and had installed in June 2020.
There's a lot of treadware and cracking on the second tire for being "new"...