On a WooCommerce site I manage, with the “Load comments with Ajax.” option enabled, WooCommerce products display a “Comments are disabled” message instead of the product’s (existing) reviews.
This site uses discourse for commenting on posts and pages, but NOT for products (i.e. it uses native wordpress for comments / reviews on products).
Wild guess: may be related to this commit: https://github.com/discourse/wp-discourse/commit/9e6818cbfb4f23d62025306b51ccf87d1bfec4dc#diff-50695af2526fb26edf1beeee1c314c91
I fixed this on my fork and put up a pull request: