When we add multiple prices for the same product to a 1-Step or 2-Step payment the product description is repeated for each price instead of just once at the top as intended.

Explanation:

The Description in Products is for the Product itself not per Price.

Since there is nowhere to add a description per each price, then this description was intended to be displayed only once for the product not repeated for each price.

This is how the Product section is designed to work. So the front end implementation should follow the same. Meaning the front end was implemented incorrectly.