Hi,
I said that you should turn off that option, not turn it on.
Also, I see that you activated the "force canonical URLs on listings" option to "use canonical URL and generate it if missing". Because of that, the system automatically filled the URLs without the ids in the "canonical URL" field of your products and thus when you change the alias it don't find the product anymore.
You would have to either turn off that "force canonical URLs on listings" option or empty the canonical URLs of your products so that the system could generate them again with the ids (or proper aliases) set in them.