Large hole in sourdough
I read through this issue on previous posts but think my situation may be different. I have been commercially baking bread for the past 12 years but want advice. I make 8-20 loaves of sourdough a night, shape them in baskets as a batard, and leave them covered in the walk in for at least 24 hours. They are baked in cast iron pots for 35 minutes lid on and 30 minutes lid off. I have been doing this for the past nine months and this is my first time encountering this problem. Is it my shaping? What could be causing this issue?