When I add a cart and checkout, then come back to the website the pricing table of that product changes. Example below.

I buy a product for 28.00 and check out.
When I come back to the website the product has changed to 2,800.00. Then in the pricing table it goes from the quantity price range so
27.00 turns to 2,700.00 and 26.00 turns to 2,600.00 and so on.

Is this a known bug? and how do you fix it.