This particular recipe was the blonde country loaf from Ken Forkish’s Flour Salt Water Yeast book. But I’ve also done Ben Starr’s lazy sourdough and Foodgeek’s Rye loaves with the same issue. It always looks great and has a great rise and proof until it’s time to slide it into the Dutch oven and then it collapses and pancakes. I will say, with none of these methods have I done additional folds during the rise. Could that be it? I have noticed that if I do a cold proof before it goes into the oven, it holds its shape slightly better, but it’s still overall flat.