If you have hidden the shop actions from the products on the shop pages, you will notice that some of the second image is showing below the first image. (see screenshot)
This is because the image height is calculated to include the add to shopping bag option on mobile (for easier user interaction).
You can fix this by editing /js/functions.js line 565 from:
productImageHeight = productImageHeight + 20;to:
productImageHeight = productImageHeight;Hope that helps.
– Kyle