It’s just over-fermented. Dear~ When I used a yogurt machine to make yogurt, I once forgot to pull out the plug after the time was up, resulting in over-fermentation and stratification. It’s like what you said is tofu. something, and it smells very sour. There is actually no harm in drinking such yogurt, but it will definitely affect the taste. If your yogurt is just a little layered and doesn't have any off-flavor, then I think you can give it a try. At worst, it’s used for making dough~ This is how my family’s spoiled yogurt is disposed of~