Hi,
I suppose that your problem was and still is that you have invalid URLs in the "canonical URL" field of your products. Probably because you changed your menu items structure after the canonical URL were filled.
And since you had the "force canonical URLs on listings" setting activated, it would use these invalid URLs on the listings. With that option turned off, it will dynamically generate the URL to the product page and thus the links will work.
Supposing that my diagnostic is correct, I would recommend to empty the "canonical URL" settings of your products, or fill it with the new valid URL of the product page.
Otherwise, it will negatively affect your SEO rankings on search engines as they rely on the canonical URL to index your pages.