Never use your bread machine to bake bread
I tried to bake bread in the Bread Man machine that my husband gave me for Christmas in 2005.
Both times, the rising dough apparently touched the top before it was baked. The top end of the loaves were sunken in.
I now use my bread machine only to make dough. It's easier than using my Kitchenaid mixer and having to do the windowpane test to make sure I've kneaded the dough for long enough.
Just toss the ingredients in the machine, press the button, and voila! Bread dough, already risen once, ready for shaping!
Bread machines weren't designed to bake sourdough breads, and sourdough breads aren't meant to be baked in a bread machine.