We have about 30% of our customers saying they can't see the existing product reviews. Also, if they click "write a review" it just reload the same product page instead of bringing up the review entry fields.
This is for the Product Reviews app by Shopify.
I can't figure out any common thread. Some are on iphones, some on laptop PCs.
I can see the reviews on our live version and "write a review" works for me and most customers.