I just had a carton of soy milk freeze from being in a spot in the back of the fridge that freezes things. When it was moved to the front of the shelf the next day it thawed and was normal.
What you describe really does sound like spoiled milk, being like buttermilk or yogurt! But you would definitely know spoiled soy milk so.... I don't know! I have had soy milk go bad and when a little spoiled is like when you add vinegar and it kinda separates, more spoiled and it's just like a thick yogurt--blurg-
I've had ice crystals in mine before- both my home made and cartoned, but it didn't thicken, and when left out returned to a normal milky state.
What you describe really does sound like spoiled milk, being like buttermilk or yogurt! But you would definitely know spoiled soy milk so.... I don't know! I have had soy milk go bad and when a little spoiled is like when you add vinegar and it kinda separates, more spoiled and it's just like a thick yogurt--blurg-
I've had ice crystals in mine before- both my home made and cartoned, but it didn't thicken, and when left out returned to a normal milky state.