Found a soft lock. I was trying to find a way to create S or Z, and at the place where you get L shape (number 3) I tried using I shape (number 8) and put myself in a bit of a bind :)
Yep, there are a few places where you can get stuck, just press Z to undo! But if you find a place where the game does break such that you can't undo, please let me know.
I had considered having the path you found lead to another shape, 6 might have worked there if the bottom of the channel was wider and further to the right, not sure why I rejected that. I might have just wanted to keep the current 6 maze, which has its own dead-end.