I'm experiencing this too, with 11 items on sale. They can be purchased all together as a bundle on the sale page with the discounted rate, but none of the individual pages show the sale and can only be purchased individually at the full price. The sale is not set up as a bundle.
This seems to be a widespread problem. I've checked about 20 other users' sales, and over half of their on-sale items do not show the discounted price on the individual page, even when their sale consists of only that one product.
EDIT - I found a way to fix it. I went in to edit the sale, removed one item from the sale, and saved the sale. Then suddenly every item showed the proper discount on the individual pages. I then went back into editing the sale to add that one item back in and save it again, and thankfully everything still shows the proper discount price.




















